Artificial intelligence (AI) chatbots are generating new forms of violence against women and girls and amplifying existing forms of abuse such as stalking and harassment. This is no accident: the platforms enable these forms of gender-based violence through deliberate design choices or by failing to implement sufficient safety features. We need to regulate AI chatbot providers now, to prevent abusive applications of such technology from becoming normalized.

The extent to which chatbots are changing violence against women and girls was laid bare in a research report I recently co-authored with colleagues. The findings are bleak. We found chatbots will initiate abuse, simulate abuse and help to enable abuse by offering personalized stalking advice. Some even normalize incest, rape and child sexual abuse by offering abusive roleplay scenarios.

Chatbots — AI systems capable of and designed to simulate human-like interaction and generate text, images, audio and video in response to user prompts — are everywhere. In the U.S., 64% of children ages 13 to 17 say that they use chatbots, with three in 10 doing so daily. Over half of adults use a chatbot at least once per week.

With these new technologies come new harms. Our report shows that chatbot design is instrumental in instigating violence against women and girls. While platform policies often prohibit harms such as harassment, grooming or sexual abuse, these scenarios can still be generated with many chatbots, and some companies do not proactively search for violations of these policies.

In one recent case in Massachusetts, a man was found guilty of cyberstalking after using AI chatbots to impersonate his victim and engage in sexual dialogue with users. One of the chatbots he used was programmed to invite users to her home address if they asked where she lived.

Training systems on user interactions risks reinforcing misogynistic and sexually violent content, while engagement-optimized and "sycophantic" design encourages chatbots to affirm harmful narratives rather than refuse them. Platform policies frequently place responsibility on users, framing abusive outputs as a user misuse issue rather than failures of chatbot safety and design.

This is why regulation of the chatbot providers is so important, to stop these practices becoming embedded. We've already seen what happens without regulation through "nudify" apps that create deepfake non-consensual intimate images. Regulation was left too late and the practice of creating deepfake images, and the harms caused to victims, had become normalized and widespread by the time governments moved to ban these tools. We argue that to avoid making the same mistakes with chatbots, the following actions need to be taken:

— Make it a criminal offense to create an AI chatbot that is designed, or can easily be used, to abuse or harass women, targeting companies or individuals who release tools that pose risks without taking reasonable steps to prevent harm. Just like reckless driving or owning a dangerous dog are punishable by law, creating a risk to the public by releasing a chatbot with insufficient protections should be brought within the scope of criminal law. Fines for companies and prison sentences for individuals responsible for creating this risk could make companies more careful to pre-empt and prevent potential harms before releasing products.

— Adopt specific AI Safety legislation. This would establish mandatory risk assessments and incorporate clear safeguards to prevent individual and societal harms, including a duty to act quickly when harms are identified, publish transparent safety information, and enable users to report incidents easily. Important state-level legislation, including in Utah, Colorado, and California, has expanded the ability for individuals, and state attorneys general, to sue AI providers that have failed to meet their obligations under the legislation. However, there has been a pushback against these state-level measures in recent years, with the U.S. government arguing they are barriers to innovation and national competitiveness.

Two main objections may be raised to our recommendations: the first, led by AI providers, is that these forms of abuse are a "user misuse" problem, and that responsibility should lie with users rather than the providers of these services. But our research shows that abuse is structurally produced by features of how chatbots are built or governed, and what they are optimized to do.

For example, to bolster engagement, some chatbots have continually driven users (including underage users) to engage in unwanted sexual messages. If a human were doing this, it would constitute grooming and/or sexual harassment. Some of the companion chatbots even offer "violent rape" or "loli" (a term for an underage girl) as options that users can choose from, legitimizing these criminal forms of abuse as mere sexual preferences. Abuse is built into the DNA of these chatbots.

The second objection — one reflected by the U.K. government’s recent announcement that it is exploring a ban on AI chatbots for under 16s — is that AI chatbots mainly pose a danger to children, and they should be the focus of regulation. But our research shows that AI chatbots can intensify abuse against adults, such as stalking or harassment, with detailed and personalized guidance and encouragement.

In the Massachusetts case, James Florence had provided AI chatbots his victim's personal information, including her employment history, her hobbies, her husband's name and place of work. The harms here are not to the user but to society at large — a ban on children’s use of chatbots would not have prevented them.

This broader societal harm does not stop when the user turns 18. We urgently need specific AI safety legislation that would protect against these harms by requiring rigorous testing and risk assessment prior to the public release of such products, and continually thereafter.

Changing the law around AI chatbot development would not only protect children but would also ensure that when those children become adults, they enjoy an AI environment that is free from bias, misogyny and violence against women and girls. That is a world we all deserve to live in.

Opinion on Live Science gives you insight on the most important issues in science that affect you and the world around you today, written by experts and leading scientists in their field.

The samurai of Japan are famous for being skilled warriors who followed a code of honor. In popular culture and museums, samurai are often depicted as men, which raises a question: Were any samurai women?

Female samurai existed and there is some evidence that they fought in battle, several experts told Live Science. But how often they fought is a matter of debate, with some scholars calling it very rare and others suggesting it happened more often.

One important point in answering this question is that the samurai were an entire social class, sometimes called the "bushi" class. Anyone born into this class was a "samurai," regardless of whether they fought or practiced any form of martial arts.

"Any woman born in the samurai status group was a 'female samurai' even if she never picked up a weapon, just as any man born into that status group was a samurai, no matter how wimpy/untrained/etc. he may have been," Sean O'Reilly, a professor of Japan studies at Akita International University, told Live Science in an email.

It's unclear how often female samurai fought in battle, however. Women who fought in battle are sometimes called "onna-musha," which translates to "women warriors."

"I must say, as an historian, that onnamusha ‪—‬ female warriors ‪—‬ were probably not as frequent or as militarily significant as most people today believe," O'Reilly said.

Some particularly good evidence for female samurai participating in battle comes from the late 19th century, near the time when the samurai class was abolished, Diana Wright, who was a professor at Western Washington University, wrote in a 2001 article in the journal "War in History."

At that time, Japan was in a civil war as supporters of the Tokugawa Shogunate, which ruled Japan from around 1603 to 1868, battled those who wanted to overthrow the shogunate and return some of the military governor's powers to the emperor. The Boshin War, as it is sometimes called, lasted from January 1868 to June 1869. During that war, there were a number of recorded instances where female samurai, who fought on the side of the shogunate, engaged in battle, Wright noted in her article.

The shogunate forces were led by the Aizu domain (a regional government in northern Japan), and during the siege of the Aizu's capital of Aizu-Wakamatsu, a group of female samurai formed their own unit known as the "Joshigun."

"Although 20 to 30 women are believed to have made up the unit, the names of only 10 are known," Wright wrote. A 22 year-old woman named Nakano Takeko was the unit's unofficial leader.

Armed with only swords and naginatas (pole weapons with curved blades that can both stab and slash), they fought in a battle at Yanagi bridge against a force equipped with rifles, Wright explained. Records indicate that Nakano Takeko killed five or six men with her naginata before she was shot down. Ultimately, the battle ended in defeat and the surviving members of the Joshigun, along with the male troops, had to withdraw to a castle.

During the time of the Tokugawa shogunate, women of the samurai class were required to undergo martial art training with the naginata so they could defend themselves and their families, Wright noted. The amount of training they received varied, with the women of the Aizu domain tending to receive a larger amount.

Remains of female warriors?

A mound located in Numazu, a city in central Japan, may hold the remains of female samurai who fought in battle, some scholars believe. The mound contains human skulls, along with other skeletal bones, and an analysis of the mound's remains was published in Japanese in 1989 in the Journal of Anthropology. The skulls are from about 105 people; all of them were young adults when they died, and about one-third were women. They date to the 16th century, and scientists interpreted them as being the remains of people who were killed in combat, likely in the Battle of Senbonhama (also known as the Battle of Senbon Matsubara), which was fought between the Takeda and Hojo clans.

This mound is "indicative that women of fighting age fought and died in sixteenth century battles," Thomas Conlan, a professor of medieval Japanese history at Princeton University, told Live Science in an email.

However, Karl Friday, a professor emeritus of history at the University of Georgia, said the mound should be regarded with caution, as we can't be sure everyone buried in it actually fought in a battle. It's possible that some of the people buried in the mound were noncombatants who were killed anyway, Friday told Live Science in an email.

Stories and legends of female samurai

A number of stories refer to female samurai fighting in battle. Perhaps the most famous was Tomoe Gozen, who lived during the late 12th century. Stories say she served a lord named Minamoto no Yoshinaka and fought in the Genpei War, which was fought between the Taira and Minamoto clans between about 1180 and 1185, Thomas Lockley, a law professor at Nihon University who has studied and written extensively about the samurai, wrote in a 2022 article in the magazine Medieval World: Culture & Conflict.

One of the chronicles, called "The Tale of the Heike," says that as "a fighter she was a match for a thousand ordinary men, skilled in arms, able to bend the stoutest bow, on horseback or on foot, ever ready with her sword to confront any devil or god that came her way" (translation by Thomas Lockley).

Another famous woman mentioned in stories was Ōhōri Tsuruhime, who lived circa 1526 to 1543. She became the chief priestess of Ōyamazumi Shrine, located on the island of Ōmishima, after her father and brothers were killed while defending the island from a daimyo (a regional governor) named Ōuchi Yoshitaka, Stephen Turnbull, a historian who has written extensively on the samurai, wrote in his book "Samurai Women: 1187-1877" (Osprey Publishing, 2012). Despite being just 16 years old, she took charge of the island's defense force and defended it from the invaders. During her defense, she claimed to have been aided by the shrine's kami (spirit) and has been compared to Joan of Arc, Turnbull noted.

Some of what's said to be Tsuruhime's armor survives today and is displayed at the shrine. Conlan said that it is a suit of 16th century armor that is "tailored to the female anatomy."

However, Friday said we should be cautious when interpreting stories like these. "We do have stories about female warriors, like Tomoe Gozen, Hangaku Gozen, Ohori Tsuruhime, Ueno Tsuruhime, and a few others, but these women are all semi-legendary — especially with regard to their participation in battles," Friday told Live Science in an email.

Regardless of how accurate the stories are, female warriors became famous. "Mythologizing female warriors of yore began in Japan's Kamakura period [circa 1185 to 1333] and intensified in the Edo period [circa 1603 to 1868], with a huge proliferation of woodblock prints showing women holding naginata and so forth," O'Reilly said. Friday said the "very fact that these women became so famous is a pretty good indication of how uncommon female warriors must have been."

Taboos about women and battle

Friday thinks it would have been very rare for female samurai to engage in battle because it was considered taboo.

"One fascinating primer on military conduct, passed down within a branch of the Hōjō family, enjoined against such things as sharing quarters with women for three days prior to battles, allowing pregnant women or women who had recently given birth to touch a warrior's weapons, riding in boats with female passengers while in route to battle, and even allowing women to look upon the backs of officers departing for campaigns!" Friday said.

"The bottom line is that while there almost certainly must have been at least a few cases of women participating in Japanese battles over the course of [the] 8th to 16th centuries … there's absolutely no good evidence to support the conclusion that women warriors were any more common in Japan than they were in medieval France or ancient Sparta, much less that this occurred often enough to justify calling it a practice or even a phenomenon," Friday said.

While the samurai class was effectively abolished during the 1870s, some of the training practices done by female samurai are still carried out today. Eric Shahan, a Japanese translator who specializes in translating martial arts texts, noted that the Yoshin School (a branch of traditional Japanese martial arts) "still practices Naginata in Kimono, reflecting the fact that women may have to suddenly take up arms — and therefore have no time to change into training gear."

Can you identify these historical objects of war? Test your smarts with our weapons of the world quiz!

Despite being surrounded by a multitude of people, urban birds may be picky about who can approach them, new research suggests.

After surveying over 37 city bird species in five European countries, experts found that the avians fled sooner when approached by women than by men. The findings, published in December 2025 in the journal People and Nature, suggest that the birds can differentiate between the sex of the person approaching them.

The researchers used each bird's distance from a person before flying away as a metric of fearfulness. But why the birds seem to be more fearful of women remains a mystery.

"As a woman in the field, I was surprised that birds reacted to us differently," study co-author Yanina Benedetti, an ecologist at the Czech University of Life Sciences Prague, said in a statement. "This study highlights how animals in cities 'see' humans, which has implications for urban ecology and equality in science. Many behavioural studies assume that a human observer is neutral, but this wasn't the case for urban birds in our study."

Outside experts agree that these findings are puzzling, but also preliminary.

"Until we have a good reason to hypothesize such differences, I remain a bit skeptical," John Marzluff, a professor emeritus in ecology at the University of Washington, told Live Science in an email. "But I am not at all skeptical that birds pay a lot of attention to us and respond to humans in ways that are important. We just need more research here to better understand why this effect was so consistent."

Baffling bird behavior

To understand whether this puzzling response was a bigger pattern rather than a few skittish encounters, the researchers used a standard measure of urban wildlife wariness: flight initiation distance, or how close a person can get before an animal flees.

The team studied the flight initiation distance in 37 species — including the common wood pigeon (Columba palumbus), carrion crows (Corvus corone), house sparrows (Passer domesticus), hooded crows (Corvus cornix), and blackbirds (Turdus merula) — across cities in the Czech Republic, France, Germany, Poland and Spain.

Some types of birds, like pigeons, seem more comfortable with human behavior and fled later or had a shorter flight initiation distance. Others, like magpies, fled early and had a longer flight initiation distance.

During the study, a man and a woman who were of comparable height and were wearing similar clothing tried to approach a bird in a city's green space by walking in a straight line and keeping their eyes on the avian. The researchers measured the distance after the bird fled. Four men and four women, all expert ornithologists, participated in the research, so the birds interacted with different pairs of people.

From 2,701 observations collected between April and July of 2023, the team found that men could get around 3 feet (1 meter) closer to the birds than women could, on average.

"I fully believe our results, that urban birds react differently based on the sex of the person approaching them, but I can't explain them right now," study co-author Daniel Blumstein, a professor in the Department of Ecology and Evolutionary Biology at UCLA, said in the statement.

Possible theories

The researchers proposed a few ideas for why the city birds flee faster from women. For example, they suggested that pheromones, body shape or gait could be factors.

"If I had to guess, I would agree with the supposition that gait is am important cue the birds are using," Marzluff said. "What I find puzzling is that one would expect such effects to be learned by a bird’s experience with various humans in their environment. If so, then there would be no reason for birds to have only experienced more threatening women. Some surely would have experienced threatening men and therefore the overall response should be no difference in response to sex."

However, the team noted in their paper that they did not have any female participants collect data while they were menstruating — when specific scent compounds in a woman's body odor intensify — an aspect that could be investigated further.

The researchers cautioned that this study is preliminary and that more data is needed to confirm this behavior isn't just a fluke.

"Follow up studies could focus on individual factors such as movement patterns, scent cues, or physical traits, testing them separately rather than grouping them under observer sex," Benedetti said.

"But how do we test this? Perhaps a study resembling Monty Python's Ministry of Silly Walks," Blumstein joked.

Are you a bird nerd? Find out with our bird quiz!

Menopause is a key period in a woman's life. This transition is often accompanied by wide-ranging physical and psychological symptoms — some of which can be debilitating and affect daily life. Menopause has also been linked to cognitive problems — such as memory, attention and language deficits.

To mitigate the effects of menopause — including hot flashes, depressive symptoms and sleep problems — many women turn to hormone replacement therapy (HRT). In England, an estimated 15% of women are prescribed HRT for menopause symptoms. In Europe, this number is even higher — varying between 18% in Spain to 55% in France.

But there's limited understanding of the effects of menopause and subsequent HRT use on the brain, cognition and mental health. To address this, we analyzed data from nearly 125,000 women from the UK Biobank (a large database containing genetic and health data from about 500,000 people).

We placed participants into three groups: pre-menopausal, post-menopausal and post-menopausal with HRT. The average age of menopause was around 49 years old. Women who used HRT typically began treatment around the same age.

In short, we found that menopause was associated with poorer sleep, increased mental health problems and even changes within the brain itself.

Post-menopausal women were more likely than pre-menopausal women to report symptoms of anxiety and depression. They were also more likely to seek help from a GP or psychiatrist and to be prescribed antidepressants.

Sleep disturbances were more common after menopause, as well. Post-menopausal women reported higher rates of insomnia, shorter sleep duration and increased fatigue.

Brain imaging analyses also revealed significant reductions in grey matter volume following menopause. Grey matter is an important component of the central nervous system which is composed mainly of brain cells. These reductions were most pronounced in regions critical for learning and memory (namely the hippocampus and entorhinal cortex) and areas key in emotional regulation and attention (termed the anterior cingulate cortex).

Notably, the hippocampus and entorhinal cortex are among the earliest affected in Alzheimer's disease, the most common form of dementia.

The changes we observed in our study could suggest that menopause-related brain changes may contribute to increased vulnerability to Alzheimer's disease later in life. This could help explain why there's a higher prevalence of dementia observed in women.

We also investigated whether taking HRT post-menopause had any effect on health outcomes. Notably, HRT did not improve the reduction in brain grey matter.

In addition, we found that women using HRT showed higher levels of anxiety and depression compared to post-menopausal women who had never used HRT. However, further analyses indicated that these differences were already present. This suggested that pre-existing mental health problems may have influenced the decision to begin using HRT rather than these symptoms being caused by the medication itself.

One potential benefit of HRT use was noted in cognitive performance — particularly for psychomotor speed. Psychomotor slowing is a hallmark feature of aging.

Post-menopausal women who had never used HRT showed slower reaction times compared with both pre-menopausal women and post-menopausal women who had used HRT. This indicates that HRT helps to slow the menopause-related declines in psychomotor speed.

HRT and menopause

There's still much we don’t know about HRT — and more evidence on its benefits and risks are still needed.

Some studies report that those taking HRT have an increased dementia risk, while others suggest a decreased risk of dementia.

More research is also needed to understand the effects of HRT and how the different routes and dosages affect menopause symptoms. But according to one UK Biobank study of 538 women, the effects don't appear to differ — regardless of factors such as the formulation, route of administration and duration of use.

Importantly, however, it's difficult to establish whether women are actually receiving an effective dose. One in four women using the highest licensed dose of HRT still had low levels of estradiol (estrogen) — around 200 picomoles per liter. Older women and HRT patch users were more likely to have lower levels.

Optimal plasma levels to relieve menopause symptoms are between 220-550 picomoles per liter. This means that for 25% of the women in the study, HRT would not have had optimal benefit for menopause symptoms.

Considering that most women go through the menopause, it’s important to resolve the question of whether HRT is beneficial — including preventing brain grey matter volume reductions and reducing the risk of dementia. It will also be important to know what the best dose and route of administration are.

There is evidence to suggest healthy lifestyle habits may mitigate these menopause-related changes in brain health.

Our work and that of other research groups shows that a number of lifestyle habits can improve brain health, cognition and wellbeing, thereby reducing the risk of cognitive decline associated with aging and dementia. This includes regular exercise, engaging in cognitively challenging activities (such as learning a new language or playing chess), having a nutritious and balanced diet, getting the right amount of good-quality sleep and having strong social connections.

Research also shows regular physical activity can increase the size of the hippocampus, which may help mitigate some of the menopause-related reductions observed in this region.

Sleep is also critically important as it supports the consolidation of memories and helps clear toxic waste byproducts from the brain — processes that are essential for memory, brain health and immune function.

Having a healthy lifestyle may offer an accessible and effective strategy to promote brain health, cognitive reserve and resilience to stress during and after the menopause transition.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

A rare Stone Age cemetery on a Swedish island reveals that some of Europe's last hunter-gatherers were buried not with their extremely close relations but with more distantly related people, according to a new DNA analysis.

However, some burials had close biological family members, including that of a teenage girl whose father's jumbled bones had been placed on top and next to her, the researchers found.

Since the site was first excavated in 1983, Ajvide on the western Swedish island of Gotland has yielded 85 graves from the Pitted Ware culture, a hunter-gatherer society that lived in the area 5,500 years ago. Although agriculture had spread across Europe along with farming communities at this time, some hunter-gatherer groups continued to live in Scandinavia, primarily hunting seals and fishing.

Ajvide was occupied for at least four centuries, and archaeologists have found tons of pottery and animal bones, in addition to a cemetery. Excavation of the cemetery revealed that eight graves contained more than one person. Researchers originally assumed that the people in the graves were closely related. But advances in ancient DNA analysis raised the possibility of fully investigating familial relationships in the Ajvide cemetery.

"As it is unusual for these kinds of hunter-gatherer graves to be preserved, studies of kinship in archaeological hunter-gatherer cultures are scarce and typically limited in scale," Tiina Mattila, a population geneticist at Uppsala University, said in a statement. Mattila led the genetic analysis of four of the burials, and the study was published Wednesday (Feb. 18) in the journal Proceedings of the Royal Society B.

In one grave, excavators had found an adult female skeleton along with the skeletons of two young children. The researchers' DNA analysis revealed that the children were a boy and a girl who were full siblings. The woman, however, was not their mother and may have been their father's sister or their half-sister.

A second grave contained the skeletons of a boy and a girl buried together. DNA analysis showed that they were third-degree relatives – who share one-eighth of their DNA – and likely cousins. In the third grave, DNA analysis of the skeletons of a girl and a young woman revealed they were also third-degree relatives, likely cousins or a great-aunt and great-niece.

And in the fourth grave, there was a young teenage girl buried on her back in an outstretched position, with a pile of bones on top and next to her. Using DNA analysis, the researchers discovered that the bones were those of the girl's father. His death probably predates hers, and his bones had likely been dug up and moved to his daughter's grave from elsewhere, the researchers said.

"Surprisingly enough, the analysis showed that many of those who were buried together were second- or third-degree relatives, rather than first-degree relatives — in other words, parent and child or siblings — as is often assumed," study co-author Helena Malmström, an archaeogeneticist at Uppsala University, said in the statement. "This suggests that these people had a good knowledge of their family lineages and that relationships beyond the immediate family played an important role."

This study of the Ajvide burials is the first to explore family relationships among Scandinavian Neolithic hunter-gatherers, according to the statement. But more work is planned, as the researchers will now analyze all the skeletons recovered from the cemetery to learn more about ancient hunter-gatherer social structure, life history and burial rites.

Stone Age quiz: What do you know about the Paleolithic, Mesolithic and Neolithic?

Ancient Olympians were renowned for their strength and agility, but were any of these athletes women? And were there other sporting opportunities in which women in ancient Greece could compete?

The ancient Olympics involved people from all over Greece and sometimes beyond and lasted from about 776 B.C. to A.D. 393. For much of this time, the restrictions against women appeared strict, wrote the writer Pausanias, who lived during the second century A.D. He noted there was a law to throw any "women who are caught present at the Olympic games" off a cliff (translation by William Jones and Henry Ormerod).

While the ancient Olympic games were largely off limits to women, there were other athletic competitions that women could compete in — particularly those involving running. There was even a series of footraces, called the Heraea (also spelled Heraia), held in honor of the goddess Hera, that took place at Olympia on the Peloponesian Peninsula, where the games were held.

Pausanias wrote that "the contest is a running event for unmarried girls," with three different age categories (translation by Waldo Sweet), and that it was held every four years at Olympia.

"Here is their method of running. They let down their hair, let the tunic hang down a little above the knee, and uncover the right shoulder as far as the breast," Pausanias wrote. Depictions of females dressed like this and engaged in athletic activity have been found on ancient Greek artifacts.

"To the victors they give crowns of olive leaves and a share of the cow which they sacrifice to Hera," Pausanias wrote, noting that the winners may also "set up statues with their names inscribed." Footrace competitions among females were also held at other ancient Greek sites.

Women also entered chariot teams (consisting of a driver and four horses) into ancient competitions — including the Olympics — but they didn't necessarily drive the chariots. Nor were they allowed to watch the Olympic games, although there were rare exceptions.

However, as the owner of a chariot team, they could claim victory. Kyniska, a sister of a king of Sparta, became the first-known female victor of the Olympic games when her chariot team won in 396 B.C. Kyniska owned and bred the winning horses, and an inscription from a statue base says that she was the "only woman in all Greece" to win the Olympics (translation by Donald Kyle).

Ancient texts and archaeological remains indicate that females also took part in other sports, such as wrestling. Evidence of formal female competitions is limited, but that doesn't mean they didn't occur.

"There is literary evidence that, especially in Sparta, females engaged in things like wrestling for educational purposes," Heather Reid, professor emeritus at Morningside University in Iowa, told Live Science in an email.

In Sparta, there was actually a requirement that young females practice wrestling, among other sports, in order to build and maintain muscle. The ancient poet Propertius, who lived during the first century B.C., wrote that he was "impressed that a naked girl may take part in games in the midst of men wrestlers without incurring criticism" (translation by Waldo Sweet). He also wrote that females in Sparta practiced pankration, an ancient form of mixed martial arts.

After marriage

The number of athletic competitions available to women after they were married seems to have been limited. Reid said that "women's athletics, like men's athletics, seems to have arisen out of rites of passage. In the case of females the ritual involved the transition from child to Parthenos … woman eligible for marriage." Reid noted that married women who owned chariot racing teams could still claim victory as their owner.

Georgia Tsouvala, a history professor at Illinois State University, said that married women in Sparta might have been able to compete in some competitions.

"I imagine that might have been possible, if the competition was local," Tsouvala told Live Science in an email. "For example, we know that Spartan women continued to use the gymnasium and palaestra [wrestling school] even after they got married and got pregnant."

Roman-controlled Greece

During the time of Roman rule over Greece, which started in the second century B.C., there appears to have been an increase in the number of female athletic competitions, with more records mentioning female footraces.

Onno van Nijf, an ancient history professor at the University of Groningen in the Netherlands, said that it's not clear why the number of female competitions increased in Roman times. The "Romans had an ambivalent attitude to Greek athletics, and a real explanation of the phenomenon has yet to be established," he told Live Science in an email.

There are a number of artifacts dating to Roman times that mention female athletes in Greece. One inscription describes a woman named Hedea who lived during the first century A.D. and won multiple competitions in foot racing and chariot racing and was awarded Athenian citizenship for her victories.

Another inscription dating to the late first century A.D., from the island of Kos, lists the members of a wrestling school on the island. All the names are men, except for a woman named Hetereia Prokilla. She and the other wrestlers are listed as "presbyteroi," a name that "can refer to a mature individual but also to important members of the city," Tsouvala said.

Whether she competed against men on the island is not clear, and we know little about her. From "the inscription we can assume that she was a member of the elite and a Roman citizen," Tsouvala said.

One of the best-known surviving artifacts that appears to depict an ancient Greek female athlete is the "Vatican runner" (also known as the "Running girl" or "Atalanta Barberini"). Dating back around 2,000 years, it shows a young woman wearing a chiton, a type of dress, similar to that described by Pausanias, and she appears to be running a race. It is now in the Vatican Museums.

This round, silver pendant was found in a 10th-century elite woman's burial in Sweden in 1920 and is the only known depiction of a pregnant Viking.

The artifact, known as the Ash Pendant, is in the collection of the Swedish History Museum. It is about 1.5 inches (4 centimeters) in diameter and made out of gilded silver. A ring partially encloses a female figure, who stands with her legs spread and hands clasped under her pregnant belly. Although the top of the pendant is worn down, lines above the woman's head suggest a crown or headdress. The woman wears a cloak buttoned at the neck and a pearl-like beaded accessory.

The pendant was discovered by Swedish archaeologist T.J. Arne in his 1920 excavation of several burial mounds at the site of Aska. Dozens of artifacts were found in the grave, including eight other pendants, four silver rings, a bone game board and an Islamic silver coin. Based on the presence of rivets and nails, the excavators suspected the woman was buried in a wooden casket that decomposed over time, and her bones suggest she was a young or middle-aged adult. It's unknown if she was pregnant or giving birth when she died.

There is some disagreement about what the unique Ash Pendant may signify about the deceased Viking woman.

According to the Swedish History Museum, the pendant may depict the Norse goddess Freyja, who was associated with pregnancy and childbirth. Freyja wore a special necklace called the Brísingamen, the descriptions of which closely match the button clasp and rows of beads on the Ash Pendant. The pendant may therefore have been a talisman for the woman in the grave.

But the Aska site also features a large, flat-topped mound that might have been the foundation for a "royal hall," according to archaeologist Martin Rundkvist, meaning the people buried in the graves were "petty royalty." They appear to have passed down the silver pendants, including the Ash Pendant, as heirlooms over several generations.

Given the range of artifacts discovered in the woman's grave, including a wolf-headed iron staff and the series of heirloom pendants, the woman may have held a prominent role as a practitioner of magic or ritual, archaeologist Neil Price has argued.

And because later graves in the Aska area lack similar ritual objects, according to a study by archaeologist Hide Gustafsson, this may mean that the Viking woman buried in the mound was the last pagan practitioner of her kind before the introduction of Christianity to the region, and that her Freyja pendant was buried with her.

For more stunning archaeological discoveries, check out our Astonishing Artifacts archives.

Human papillomavirus (HPV) vaccines can dramatically reduce the rate of infections that cause cervical cancer, even in people who haven't been vaccinated, a new long-term study reveals.

Most cases of cervical cancer are caused by high-risk HPV viruses, which can drive changes in cells that turn them cancerous. Two types of high-risk HPV are most likely to cause cervical cancer. After the introduction of HPV vaccines in the U.S., the shots reduced the amount of people testing positive for those cervical-cancer-causing viruses by a whopping 98.4% in vaccinated teens and young women in Cincinnati, the focus of the new study. Meanwhile, in unvaccinated people of the same age, the rates of infection still fell by 71.6% in the same time period.

This demonstrates that HPV vaccines, introduced in the U.S. in 2006, can lead to herd immunity, which is when a population becomes so resistant to the spread of a virus that even unvaccinated people are indirectly protected.

HPV is the most common sexually transmitted infection worldwide; that stat includes both low- and high-risk strains. While it's primarily known for its potential to cause cervical cancer, exposure to high-risk HPV can also lead to other cancers in both sexes, according to a statement released by the researchers. These include those affecting the anus, head and neck.

Scientists have known for many years that HPV vaccines are highly effective, significantly reducing the rate of cervical precancers in young U.S. women and preventing cervical cancer deaths. However, the new 17-year study, published Monday (Sept. 29) in the journal JAMA Pediatrics, found that the vaccines have also reduced high-risk cervical infections in adolescent girls and young women at increased risk of HPV, even when they themselves were not vaccinated.

Nearly all sexually active people get HPV at some point in their lives. The infections are typically symptomless and tend to go away on their own within two years. However, in some cases, they can persist and ultimately cause cancers.

A 2020 study published in The Lancet Global Health estimated that in 2018, there were 690,000 cases of cancer attributed to HPV worldwide, including 620,000 in women and 70,000 in men. Cervical cancer accounted for about 80% of these cancer cases. So while most people don't get cancer as a result of an HPV infection, the virus' prevalence makes it a major public health problem.

In the new study, the researchers analyzed data from six surveillance studies in Cincinnati, collected from 2006 — the year before the vaccine became available there — to 2023. The study included 2,335 adolescent girls and young women between 13 and 26 years old. They focused primarily on participants who had an increased risk for HPV because they had multiple sexual partners or a history of sexually transmitted infection.

Multiple HPV vaccines have been introduced since 2006, and this study assessed the effectiveness of three versions: the 2-valent version, which guards against HPV 16 and HPV 18, the HPV responsible for more than 70% of cervical cancers; the 4-valent version, which additionally covers HPV 6 and HPV 11; and the 9-valent versions, which protect against another five types.

During the study period, the rate of HPV infections fell as the vaccines became available and the proportion of vaccinated participants increased, from 0% to 82%. Infections covered by the 2-valent vaccine dropped by 98.4% among vaccinated individuals, while the remaining HPV types covered by the 4-valent and 9-valent vaccines dropped by 94.2% and 75.7%, respectively.

The 9-valent vaccine was just as protective as the 2-valent and 4-valent vaccines in clinical trials, lead study author Dr. Jessica Kahn, a professor of pediatrics at the Albert Einstein College of Medicine in New York, told Live Science. But the decline in virus types targeted by the 9-valent vaccine was lower in this real-world scenario because it was licensed more recently, meaning fewer participants had received at least one dose of that version by the time of the study.

Among unvaccinated participants, HPV 16 and HPV 18 infections dropped by 71.6% in the study population, while the remaining two strains covered by the 4-valent vaccine dropped by 75.8%, indicating a high degree of herd immunity. The researchers didn't have enough data to effectively look at all the strains covered by the newer 9-valent vaccine in unvaccinated people.

The findings are good news for highly vaccinated areas, but rates of cervical cancer are higher in poorer countries than in the U.S. Globally, only 31% of adolescent girls and 8% of adolescent boys between 9 and 14 years old have received one dose of an HPV vaccine, according to 2024 World Health Organization data, the latest available. Increasing vaccine uptake worldwide could have dramatic impacts.

"By expanding uptake of this highly safe and effective vaccine, and ensuring access to screening and treatment, we can achieve one of the greatest public health victories of our time: the elimination of cervical cancer worldwide," Kahn said.

This article is for informational purposes only and is not meant to offer medical advice.

In this adapted excerpt from "Not Just for the Boys: Why We Need More Women in Science" (Oxford University Press, 2023), physicist Athene Donald examines the role of bias against women in scientific publishing, and its pervasiveness that still persists among academia.

In judging individuals, it might be thought that there are appropriate quantitative and objective metrics to be used. In reality, such metrics can be seen to disadvantage women. Different disciplines and different countries may exhibit these tendencies to a greater or lesser extent. Letters of reference — in science as elsewhere — tend to use fewer stand-out adjectives about women than men, meaning their chance of progression is reduced.

Women's papers are cited less; their grants are on average smaller; and their papers have a harder time getting past reviewers. A recent study of referees' comments highlighted just how unpleasant, not to mention unhelpful, referee comments may be. One example stated: "This paper is, simply, manure." Hardly constructive criticism.

And misogyny can feed into reviewers' comments, sometimes explicitly, as in the case of another review quoted in the same paper: "The first author was a woman. She should be in the kitchen, not writing papers." I would like to think that referee was blacklisted thereafter by the editor concerned, but the fact the editor saw fit to pass the comments on makes me think that was unlikely.

Faced with such responses, many researchers' confidence, and particularly those of women who are in the minority in a field, may be so shaken that they step back or quit altogether.

Underpinning many of the obstacles I've just outlined is bias, unconscious though it may be. Overt discrimination is not only illegal, it is now less evident. Rita Colwell, the bacteriologist and first woman to head up the U.S.'s major funding agency, the National Science Foundation (NSF) was told at the start of her career in 1956 that "we don't waste fellowships on women." This remark made her angry, but it didn't stop her in her professional tracks, as it might have for many women then and since.

Most senior academics would probably be more cautious to express such an opinion outright today, whether or not they privately harbored such thoughts. But it is not necessary to be aware of thinking that women are somehow second-class citizens; that opinion may seep into actions unconsciously.

Bias of this subterranean sort — variously known as unconscious or implicit bias — has come under intense scrutiny in recent years, as it should. Bias, at the individual level, acts as an unconscious reaction to all the stereotypes we have been fed since birth, and comes in many shapes and forms. It can be compared with Nobel Prize-winning Israeli psychologist Daniel Kahneman's two modes of thinking, System I and System 2.

System 1, which operates automatically and quickly, in an essentially involuntary way, would give rise to unconscious bias of the sort that decides a woman is not as capable of being a scientist as a man but would be expected to be very good at childminding or nurturing more generally.

System 2, the slower thinking process, takes the time to think through such a decision. That process allows the bias against women in that first thought to be teased out, confronted and, hopefully, rejected. Organizations that introduce unconscious bias training need to ensure that the need for moving on to slower, more considered (i.e. System 2) thinking is impressed on the individual, not imagine that the training is simply some sort of tickbox exercise telling people they should not be biased.

The latter, too commonly seen in online courses in particular, is totally insufficient to see outcomes shift, the only measure of the success of such a program. It may even backfire.

The subtle ways in which unconscious bias can operate in an academic setting was spelled out at length in Virginia Valian's classic book "Why So Slow?" (MIT Press, 1998) about the progression of women in academia. Despite Valian's book being a quarter of a century old, it is still a sobering read, highlighting all the different places where disadvantage may accrue across the university sector (and not just STEM).

Related: 30 amazing women in science and math

What is the hard evidence, beyond anecdote and suspicion, that unconscious bias impacts on women's careers? Increasing numbers of studies show, in many different guises, just how potent such bias can be.

One of the most striking classes of study is that which compares the reactions of both men and women to identical CVs submitted under a typically male and a typically female name. Valian highlights a study from as far back as 1975 by L.S. Fidell, which demonstrates bias in her own field of psychology. Many studies since have gone on to demonstrate the pervasiveness of such bias, which does not seem to be disappearing.

For instance, in one much-cited study, faculty were sent identical CVs to evaluate, differing only in whether the name at the top appeared to be male or female. These were application materials for an undergraduate science student who had ostensibly applied for a science laboratory manager position. Both male and female faculty were more likely to "hire" the man, as well as offer him more support/training and a higher salary than the woman, despite the identical track records.

The late 1990s saw not only the publication of Valian's book, but also a paper regarding data from the Swedish Medical Research Council concerning biomedical fellowships, which used a Freedom of Information request to obtain the actual evaluation sheets used by the peer-review panel. Sweden, it should be noted, is generally regarded as one of the most egalitarian societies in the world when it comes to gender issues, but the findings would not have led a reader to make that assessment.

The title of the paper presenting the results of this study gives the game away: "Nepotism and Sexism in Peer-Review." Using an array of metrics to devise a figure of merit for impact, it demonstrated graphically how great a difference there was in evaluators' competence scores for men and women objectively assessed to have demonstrated equivalent impact.

The authors' analysis showed that this discrepancy amounted to the equivalent of three papers in a high-ranking journal, such as Nature, or the phenomenal difference of 20 papers in a moderately highly ranked journal. Equally worrying was personal bias, the nepotism of the title, when an applicant was known to a panel member.

Despite that particular person not being allowed to take part in the evaluation itself, as is customary with such funding panels, it transpired that the other panel members scored anyone known to have such an association more highly.

Bias comes in many forms, regardless of how much processes such as excluding a known associate from making the relevant judgement, may attempt to overcome them. When this study appeared, back in 1997, many women already had suspicions that they were being treated unfairly, or at least differentially compared with men.

For far too many of us, the message of the 1988 "Miss Triggs" cartoon will have felt painfully familiar then, and may still do so now. To counter this sort of behavior it is important for those around the table to chip in, to remind everyone that Miss Triggs did just say this and it is good that Mr X agrees.

This technique was brought more forcefully into the public's eyes by female staffers in the Obama White House, who called it amplification. As the Washington Post described it: When a woman made a key point, other women would repeat it, giving credit to its author. This forced the men in the room to recognize the contribution — and denied them the chance to claim the idea as their own.

Every committee around the world, in academia or not, could do with more pushing back on bad behavior from other committee members.

The other tendency seen only too often at committees, debates, and other potentially confrontational situations, is that when men talk over another committee member it is typically a woman. Again, American politics shows a clear example of how to deal with this arrogant behavior; in the 2020 Vice Presidential debate, Kamala Harris calmly said over and over, "Mr Vice President, I'm speaking." Many people would, however, find it easier if someone else, an ally male or female, made that very same point for them.

© Athene Donald. Extract from Not Just for the Boys: Why We Need More Women in Science published by Oxford University Press in May 2023, available in paperback and eBook formats, £16.99.

Pregnant women wielding swords and wearing martial helmets, foetuses set to avenge their fathers — and a harsh world where not all newborns were born free or given burial.

These are some of the realities uncovered by the first interdisciplinary study to focus on pregnancy in the Viking age, authored by myself, Kate Olley, Brad Marshall and Emma Tollefsen as part of the Body-Politics project. Despite its central role in human history, pregnancy has often been overlooked in archaeology, largely because it leaves little material trace.

Pregnancy has perhaps been particularly overlooked in periods we mostly associate with warriors, kings and battles — such as the highly romanticised Viking age (the period from AD800 until AD1050).

Topics such as pregnancy and childbirth have conventionally been seen as "women's issues", belonging to the "natural" or "private" spheres — yet we argue that questions such as "when does life begin?" are not at all natural or private, but of significant political concern, today as in the past.

In our new study, my co-authors and I puzzle together eclectic strands of evidence in order to understand how pregnancy and the pregnant body were conceptualised at this time. By exploring such "womb politics", it is possible to add significantly to our knowledge on gender, bodies and sexual politics in the Viking age and beyond.

First, we examined words and stories depicting pregnancy in Old Norse sources. Despite dating to the centuries after the Viking age, sagas and legal texts provide words and stories about childbearing that the Vikings' immediate descendants used and circulated.

We learned that pregnancy could be described as "bellyful", "unlight" and "not whole". And we gleaned an insight into the possible belief in personhood of a foetus: "A woman walking not alone."

An episode in one of the sagas we looked at supports the idea that unborn children (at least high-status ones) could already be inscribed into complex systems of kinship, allies, feuds and obligations. It tells the story of a tense confrontation between the pregnant Guðrún Ósvífrsdóttir, a protagonist in the Saga of the People of Laxardal and her husband's killer, Helgi Harðbeinsson.

As a provocation, Helgi wipes his bloody spear on Guđrun's clothes and over her belly. He declares: "I think that under the corner of that shawl dwells my own death." Helgi's prediction comes true, and the foetus grows up to avenge his father.

Another episode, from the Saga of Erik the Red, focuses more on the agency of the mother. The heavily pregnant Freydís Eiríksdóttir is caught up in an attack by the skrælings, the Norse name for the indigenous populations of Greenland and Canada. When she cannot escape due to her pregnancy, Freydís picks up a sword, bares her breast and strikes the sword against it, scaring the assailants away.

Related: 'If it was a man, we would say that's a warrior's grave': Weapon-filled burials are shaking up what we know about women's role in Viking society

While sometimes regarded as an obscure literary episode in scholarship, this story may find a parallel in the second set of evidence we examined for the study: a figurine of a pregnant woman.

This pendant, found in a tenth-century woman's burial in Aska, Sweden, is the only known convincing depiction of pregnancy from the Viking age. It depicts a figure in female dress with the arms embracing an accentuated belly — perhaps signaling connection with the coming child. What makes this figurine especially interesting is that the pregnant woman is wearing a martial helmet.

Taken together, these strands of evidence show that pregnant women could, at least in art and stories, be engaged with violence and weapons. These were not passive bodies. Together with recent studies of Viking women buried as warriors, this provokes further thought to how we envisage gender roles in the oft-perceived hyper-masculine Viking societies.

Missing children and pregnancy as a defect

A final strand of investigation was to look for evidence for obstetric deaths in the Viking burial record. Maternal-infant death rates are thought to be very high in most pre-industrial societies. Yet, we found that among thousands of Viking graves, only 14 possible mother-infant burials are reported.

Consequently, we suggest that pregnant women who died weren't routinely buried with their unborn child and may not have been commemorated as one, symbiotic unity by Viking societies. In fact, we also found newborns buried with adult men and postmenopausal women, assemblages which may be family graves, but they may also be something else altogether.

We cannot exclude that infants — underrepresented in the burial record more generally — were disposed of in death elsewhere. When they are found in graves with other bodies, it's possible they were included as a "grave good" (objects buried with a deceased person) for other people in the grave.

This is a stark reminder that pregnancy and infancy can be vulnerable states of transition. A final piece of evidence speaks to this point like no other. For some, like Guđrun's little boy, gestation and birth represented a multi-staged process towards becoming a free social person.

For people lower on the social rung, however, this may have looked very different. One of the legal texts we examined dryly informs us that when enslaved women were put up for sale, pregnancy was regarded as a defect of their bodies.

Pregnancy was deeply political and far from uniform in meaning for Viking-age communities. It shaped — and was shaped by — ideas of social status, kinship and personhood. Our study shows that pregnancy was not invisible or private, but crucial to how Viking societies understood life, social identities and power.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

In Birka, Sweden, there is a roughly 1,000-year-old Viking burial teeming with lethal weapons — a sword, an ax-head, spears, knives, shields and a quiver of arrows — as well as riding equipment and the skeletons of two warhorses. Nearly 150 years ago, when the grave was unearthed, archaeologists assumed they were looking at the burial of a male warrior. But a 2017 DNA analysis of the burial's skeletal remains revealed the individual was female.

Skeptics scrambled to explain away the evidence, said Charlotte Hedenstierna-Jonson, an archaeologist at Uppsala University in Sweden and first author of the 2017 study.

Even now, despite further studies strengthening the case for the Birka individual's martial profession, some archaeologists still insist she wasn't a warrior.

The Birka controversy highlights the fraught archaeological debate about the existence of Viking women warriors. Viking mythology and lore are filled with tales of women who lived for battle and engaged in violence, but whether these stories reflect real life is unsettled.

Across Scandinavia, at least a few dozen women from the Viking Age (A.D. 793 to 1066) were buried with war-grade weapons. Collectively, these burials paint a picture that clashes violently with the hypermasculine image of the bearded, burly Viking warrior that has dominated the popular imagination for centuries. And it's possible that, due to gendered assumptions, archaeologists may be systematically undercounting the number of Viking women buried with weapons.

The finds hint at a nuanced picture of Viking society — one where most warriors were men but a person's class and profession had the biggest impact on who went to war.

"Women can be as strong, as skilled, as fast as men," said Leszek Gardeła, an archaeologist at Ludwig Maximilian University of Munich and author of "Women and Weapons in the Viking World: Amazons of the North" (Casemate, 2021). "There is nothing in the biology there that would prevent them from being warriors."

Still, the poor preservation of Scandinavian graves, the enigmatic nature of Viking burials and the lack of historical texts leaves the meaning of many female burials up for debate. And even if women warriors existed, their significance in the broader Viking culture is unclear, Ole Kastholm, a prehistoric archaeologist and senior researcher at Roskilde Museum in Denmark, told Live Science.

"It's an area where we can't find a secure answer," he said.

Related: What's the farthest place the Vikings reached?

What the burials hold

Across Sweden, Norway, Denmark and Iceland, there are thousands of known Viking burials typically thought to be of male warriors. In contrast, we know of around 30 graves in which women were buried with obvious martial equipment such as spearheads and shields; of these roughly 30, only three have swords.

Of the known Viking Age burials, "statistically speaking, there would be less than 1%" of women buried with weapons among graves of men buried with weapons, Gardeła told Live Science.

But there are many more female burials that included other gear, such as shield bosses (a round protective metal piece at the shield's center), or possible weapons, such as arrowheads and ax-heads. Interpreting the latter burials is especially challenging because axes and arrowheads were used in battle, but they were also tools for hunting and farmwork.

But one of the main reasons the female-warrior question is so controversial is that many Viking burials aren't in great condition.

The Birka burial is one example. In 1878, workers used dynamite to blast open the grave, damaging it in the process. Untrained locals then helped excavate the grave. This poor excavation work has given naysayers room to argue that the chamber once held a double burial with a man.

According to the skeptics, "a woman would never be strong enough to use those weapons" — an argument that was ridiculous to Hedenstierna-Jonson, who had actually handled them.

"There were all these opinions rather than scientific facts," Hedenstierna-Jonson told Live Science.

Yet modern-era damage isn't the biggest obstacle to analysis. In many cases, bones and cremated remains are partially or completely decayed before archaeologists get a peek, largely due to Scandinavia's acidic soil. "We need very good preservation of the skeletons before we can determine the sex" via DNA analysis or bone studies, Kastholm said. "So even though the Viking Age has been investigated for like 150 years or more, it has not been that easy" to assess these graves.

As a result, archaeologists often guessed the deceased's sex based on grave goods, such as mirrors, weaving tools and brooches, which archaeologists assumed were typically buried with females, and battle-related weapons, which archaeologists thought were typically buried with males. If a Viking Age sword was the only item recovered, for example, it was nearly always assumed to be a male grave.

So it's possible archaeologists may be systematically undercounting Viking women who were buried with weapons.

"We could have a lot more of these [female] graves than we know about," said Marianne Moen, head of the Department of Archaeology at the Museum of Cultural History at the University of Oslo, calling the situation a catch-22. "You excavate a grave in Norway, you find a sword and you go, 'Oh, it's a man.' And then, 'isn't it funny how all the swords are buried with men?'"

In some instances, if a burial had both male- and female-associated artifacts, it is assumed, possibly incorrectly, that it was a double burial with a male and a female.

Even with that potential bias, there is strong evidence that some women were buried with war-related objects across Scandinavia. Norway has several of what have been nicknamed "shield-maiden" burials, after the women warriors of Scandinavian folklore. One is the Nordre Kjølen burial in Solør, which had a young adult — likely a female, based on a skeletal analysis — interred with a sword, an ax head, a spearhead, arrowheads, a shield boss, a horse skeleton and tools.

A second is the female boat burial from Aunvoll in Nord Trøndelag, in which a female was interred with a sword, eight gaming pieces, a sickle, a spearhead, shears, a knife and tools. The Klinta burial in Öland, Sweden has the cremated remains of what are thought to be an elite woman with valuable metal artifacts, including an ax-head, knives and an iron staff, causing some to wonder if she was a völva, or a Viking Age sorceress.

And although they're not buried with sharp weapons, "there's quite a few female burials on the west coast of Norway that have shield bosses and nobody likes to talk about them," Moen told Live Science.

Difficult to interpret

Still, many archaeologists struggle to make sense of these graves because the Vikings didn't have a consistent way of dealing with the dead.

"When we look at the Viking Age burials as a whole, they are weird and there's a great variation," Kastholm said. For instance, one had only a foot in it. Another was a triple burial of "a woman, then another woman buried some years later and then a half man buried later."

These mysterious, inconsistent burials make it hard to make straightforward conclusions.

Take the example of a grave discovered in Gerdrup, Denmark, in 1981, Kastholm said. A woman was buried with a spear, with large stones on her body. Her adult son, who had bound ankles and may have been hanged, was also in the grave.

The spear could be a sign the woman was a warrior. But that's not how Kastholm interprets the grave. Instead, he thinks that the son was hanged in devotion to Odin, the stones represent the woman's high status, and the valuable "spear was thrust into the bottom of the grave in a concluding ritual that dedicated the dead to Odin," he co-wrote in a 2021 study. This would have been a form of complex "mortuary theater," a play of sorts that would have been enacted at the grave site, which research suggests may have been common.

As for the Birka burial, Kastholm doesn't dispute that the deceased was biologically female and that she was buried with many weapons. "I'm totally convinced by that," he said. "If that means she was a warrior, I'm not convinced there. But that would go for male graves as well."

What historical texts tell us

To put the burials of women with weapons into context, archaeologists have looked at historical texts.

The Vikings left behind only a few thousand runic inscriptions. So most descriptions of warlike women and "shield maidens" come from semihistorical works written during the post-Viking medieval period. For instance, in "Gesta Danorum," a semifictional history of Denmark by Saxo Grammaticus (who lived circa 1150 to 1220), the warrior woman Lagertha travels with a group of women dressed as men, marries a Viking king who later divorces her, and still fights with him in a pivotal battle.

And some sagas, such as The Saga of Hervör and Heidrek, describe Norse women taking up arms to help protect family property, according to a 1986 analysis. Only men could inherit property, so if a man had only daughters, one was sometimes compelled to step into the role of a warrior as a "functional son" who could protect the family's interests, according to the study.

The Icelandic sagas, written by people who were likely the Viking's descendants in the 13th and 14th centuries, include stories about "women leading troops and engaging in acts of violence," Moen wrote in a 2021 article.

But are these stories evidence that Viking women were warriors in real life? Or did some stories have other mythical or mystical significance?

Some evidence points toward the latter. Sagas in which women wield weapons like axes often have magical overtones. In the Old Norse Ljósvetninga saga, for instance, a cross-dressing Norse sorceress strikes the water with an ax to see into the future. Axes are frequently associated with magic in folk traditions from Scandinavia, Finland and Central Europe, Gardeła noted in a 2021 article.

Gender wasn't destiny

After the Viking Age, the stereotype of the burly and ruthless male Viking warrior arose in the medieval sagas that detailed their exploits, and again in the late 19th century during Scandinavia and Iceland's National Romantic period. But it's possible that Viking Age society was "less governed by binary gendered ideals and more by fluid social obligations," Moen wrote in the 2021 article.

This would mean there wasn't a simple male-female dichotomy in who did what. This is seen in Viking Age grave goods. For instance, at Viking Age cemeteries in Vestfold, Norway, Moen found that although weapons were more common in male graves, they were also found in female burials. Likewise, while jewelry was more pronounced in female graves, 40% of male graves also had them, "hardly a negligible proportion," she wrote in the article.

Given how much violence permeated Viking society, "it would be naïve to think that only one half of the population was invested in it," she wrote in the article.

But people should not see this as female warriors filling a "man's role," Kastholm said. Rather, "warrior" was probably a profession, like modern-day firefighting, in which most were male but some were female.

Even among Viking Age men, being a "warrior" meant different things. Farmworkers, fishers and other peasants may have fought occasionally. But for the most part, the warriors were the social elite.

"Your biological sex was a factor [in your profession], but it was not the main factor," Hedenstierna-Jonson said. "The main factor was your role and your position and your family."

Still, people should be cautious in using information about these burials to infer how gender was perceived in Viking society, Moen said.

"I don't think it even necessarily indicates any kind of gender equality," she said. "What I do think is that you have much evidence women could be warriors and were warriors at certain times and in certain conditions."

"Occam's razor"

Moen splits archaeologists into three groups: those who think the burials clearly show that female warriors existed; people who say, "Yes, obviously women could be buried with weapons, but we need to question what it means"; and naysayers who think there's no way women actually used the weapons they were buried with. "They find it really quite troubling, and they go to very long lengths of explaining it away," she said.

To Moen, the evidence of female Viking warriors is right in front of us.

"Occam's razor, you know — the simplest explanation is usually the best," she said. "If you find a woman with a sword, then you should interpret it the same as you would a man with a sword."

In the end, Kastholm thinks "there will always be a lot of debate. And that debate is more about our time" and our modern-day attachment to gendered stereotypes about the Vikings than it is about the archaeological evidence, he said.

"Of course there were warriors in the Viking Age, and I'm pretty sure that some of them were female," Kastholm said. Yes, many graves are tricky to pin down, but at least a few have an impressive number of hard-core weapons buried with them.

"If it was a man," he said, "we would say 'that's a warrior grave."

Editor's Note: In this article, we are referring to biological sex, as it's impossible to know the gender of these deceased individuals.

Viking quiz: How much do you know about these seaborne raiders, traders and explorers?

Archaeologists in Peru have discovered the burial of an elite woman with remarkable grave goods, including decorative crafts made from a toucan's beak and macaw feathers.

The woman lived sometime between 3000 and 1800 B.C., and her well-preserved body was found in the ruins of the ancient town of Aspero, which is located in western Peru, about 0.4 miles (0.7 kilometers) from the Pacific Ocean, Peru's Ministry of Culture said in a translated statement.

Her body was wrapped in a variety of materials, including cotton fabrics, bundles of plant fiber, mats and netting. Her skin, hair and nails were well preserved, which is unusual because human remains in the area usually have only bones, the statement said.

The elite woman died between 20 and 35 years of age and was buried with a variety of grave goods, including a panel embroidered with macaw feathers, a toucan's beak inlaid with green and brown beads, an Amazonian snail shell, about 30 sweet potatoes and a fishing net.

The woman's identity is unknown, but she seems to have been someone of a high social rank, the statement said.

She lived at a time when a culture known as the Caral civilization flourished in the area. It was known for its sizable towns and cities and is named after the archaeological site of Caral (also known as the sacred city of Caral-Supe), a 1,300-acre (526 hectares) city that contained pyramids and temples, UNESCO notes. The Caral civilization brought urban life to the region on a scale that it had not had before.

During the time that Caral civilization thrived, and when this woman would have lived, the town of Aspero had at least 22 architectural complexes, and its people appear to have been involved in fishing and trade, the statement said.

Archaeologists noted that it seems that women who lived in this civilization could attain high social rank. In 2016, archaeologists at Aspero found the remains of a woman buried with a variety of grave goods, including four brooches that were carved into the shapes of birds and monkeys. She is now called the "Lady of Four Tupus"; "tupu" is a Quechua word for brooch, and archaeologists think she was also an elite individual because of the items buried with her. (Today the Quechua can be found around the world with large numbers living in either Peru, Bolivia, Ecuador, Chile, Colombia or Argentina.)

The Caral civilization didn't have a known writing system, so scholars don't know the names or titles that people held. Therefore, they must rely on archaeological finds to determine how the people lived. Scholars also don't know the historical names of Caral and Aspero.

Archaeologists are now analyzing the woman's body and grave goods to find out more about her health, what she ate and how she died. Excavations at Aspero have been ongoing for 20 years, and more finds will likely be made in the future.

A simple difference in the genetic code — two X chromosomes versus one X chromosome and one Y chromosome — can lead to major differences in heart disease. It turns out that these genetic differences influence more than just sex organs and sex assigned at birth — they fundamentally alter the way cardiovascular disease develops and presents.

While sex influences the mechanisms behind how cardiovascular disease develops, gender plays a role in how health care providers recognize and manage it. Sex refers to biological characteristics such as genetics, hormones, anatomy and physiology, while gender refers to social, psychological and cultural constructs. Women are more likely to die after a first heart attack or stroke than men. Women are also more likely to have additional or different heart attack symptoms that go beyond chest pain, such as nausea, jaw pain, dizziness and fatigue. It is often difficult to fully disentangle the influences of sex on cardiovascular disease outcomes versus the influences of gender.

While women who haven't entered menopause have a lower risk of cardiovascular disease than men, their cardiovascular risk accelerates dramatically after menopause. In addition, if a woman has Type 2 diabetes, her risk of heart attack accelerates to be equivalent to that of men, even if the woman with diabetes has not yet gone through menopause. Further data is needed to better understand differences in cardiovascular disease risk among nonbinary and transgender patients.

Despite these differences, one key thing is the same: Heart attack, stroke and other forms of cardiovascular disease are the leading cause of death for all people, regardless of sex or gender.

We are researchers who study women's health and the way cardiovascular disease develops and presents differently in women and men. Our work has identified a crucial need to update medical guidelines with more sex-specific approaches to diagnosis and treatment in order to improve health outcomes for all.

Related: 9 heart disease risk factors, according to experts

Gender differences in heart disease

The reasons behind sex and gender differences in cardiovascular disease are not completely known. Nor are the distinct biological effects of sex, such as hormonal and genetic factors, versus gender, such as social, cultural and psychological factors, clearly differentiated.

What researchers do know is that the accumulated evidence of what good heart care should look like for women compared with men has as many holes in it as Swiss cheese. Medical evidence for treating cardiovascular disease often comes from trials that excluded women, since women for the most part weren't included in scientific research until the NIH Revitalization Act of 1993. For example, current guidelines to treat cardiovascular risk factors such as high blood pressure are based primarily on data from men. This is despite evidence that differences in the way that cardiovascular disease develops leads women to experience cardiovascular disease differently.

In addition to sex differences, implicit gender biases among providers and gendered social norms among patients lead clinicians to underestimate the risk of cardiac events in women compared with men. These biases play a role in why women are more likely than men to die from cardiac events. For example, for patients with symptoms that are borderline for cardiovascular disease, clinicians tend to be more aggressive in ordering artery imaging for men than for women. One study linked this tendency to order less aggressive tests for women partly to a gender bias that men are more open than women to taking risks.

In a study of about 3,000 patients with a recent heart attack, women were less likely than men to think that their heart attack symptoms were due to a heart condition. Additionally, most women do not know that cardiovascular disease is the No. 1 cause of death among women. Overall, women's misperceptions of their own risk may hold them back from getting a doctor to check out possible symptoms of a heart attack or stroke.

These issues are further exacerbated for women of color. Lack of access to health care and additional challenges drive health disparities among underrepresented racial and ethnic minority populations.

Sex difference in heart disease

Cardiovascular disease physically looks different for women and men, specifically in the plaque buildup on artery walls that contributes to illness.

Women have fewer cholesterol crystals and fewer calcium deposits in their artery plaque than men do. Physiological differences in the smallest blood vessels feeding the heart also play a role in cardiovascular outcomes.

Women are more likely than men to have cardiovascular disease that presents as multiple narrowed arteries that are not fully "clogged," resulting in chest pain because blood flow can't ratchet up enough to meet higher oxygen demands with exercise, much like a low-flow showerhead. When chest pain presents in this way, doctors call this condition ischemia and no obstructive coronary arteries. In comparison, men are more likely to have a "clogged" artery in a concentrated area that can be opened up with a stent or with cardiac bypass surgery. Options for multiple narrowed arteries have lagged behind treatment options for typical "clogged" arteries, which puts women at a disadvantage.

In addition, in the early stages of a heart attack, the levels of blood markers that indicate damage to the heart are lower in women than in men. This can lead to more missed diagnoses of coronary artery disease in women compared with men.

The reasons for these differences are not fully clear. Some potential factors include differences in artery plaque composition that make men's plaque more likely to rupture or burst and women's plaque more likely to erode. Women also have lower heart mass and smaller arteries than men even after taking body size into consideration.

Reducing sex disparities

Too often, women with symptoms of cardiovascular disease are sent away from doctor's offices because of gender biases that "women don't get heart disease."

Considering how symptoms of cardiovascular disease vary by sex and gender could help doctors better care for all patients.

One way that the rubber is meeting the road is with regard to better approaches to diagnosing heart attacks for women and men. Specifically, when diagnosing heart attacks, using sex-specific cutoffs for blood tests that measure heart damage — called high-sensitivity troponin tests — can improve their accuracy, decreasing missed diagnoses, or false negatives, in women while also decreasing overdiagnoses, or false positives, in men.

Our research laboratory's leaders, collaborators and other internationally recognized research colleagues — some of whom partner with our Ludeman Family Center for Women's Health Research on the University of Colorado Anschutz Medical Campus — will continue this important work to close this gap between the sexes in health care. Research in this field is critical to shine a light on ways clinicians can better address sex-specific symptoms and to bring forward more tailored treatments.

The Biden administration's recent executive order to advance women's health research is paving the way for research to go beyond just understanding what causes sex differences in cardiovascular disease. Developing and testing right-sized approaches to care for each patient can help achieve better health for all.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Natural selection is happening among humans right now — high up in the mountains of Nepal, scientists have discovered.

The new research suggests that, compared to their peers, ethnic Tibetan women who are physiologically better adapted to living in the low-oxygen conditions at high altitudes bear more children. This hints that these beneficial traits are currently being "selected for," meaning there's an evolutionary pressure to pass them on to the next generation.

In other words, natural selection is occurring.

The researchers revealed their findings in a study published Oct. 21 in the journal PNAS. The study looked at more than 400 women, ages 46 to 86, who live in villages located in the Upper Mustang District of Nepal on the border with Tibet. The villages sit 11,500 to 13,500 feet (3,500 to 4,100 meters) above sea level.

People who live at high altitudes face harsh environmental conditions, including low air pressure that reduces the amount of oxygen available in the body. These low oxygen levels can cause tissues to stop functioning, leading to symptoms such as confusion and difficulty breathing. In more severe cases of this condition, called hypoxia, people can develop deadly illnesses like acute mountain sickness or high-altitude cerebral edema, in which the brain swells.

Related: Gene mutation helps Andean highlanders thrive at altitude, and 'living fossil' fish live deep underwater

Low-oxygen environments are especially challenging for pregnant women at higher altitudes, due to a heightened risk of preeclampsia, a potentially fatal blood-pressure condition, and are more likely to give birth to babies with low birth weights. Therefore, in populations living at high altitudes, there may be strong selective pressures for traits that help increase survival, both during and after pregnancy.

Previous research has shown that Tibetans have physiological traits and versions of genes that help them to survive in low-oxygen environments more easily than people without these characteristics. In the new study, researchers wanted to see if they could link these genetic and physiological traits with reproductive success to show that evolution is happening via natural selection in these populations.

In biology, "reproductive success" is typically measured through a tally of how many offspring an organism has produced, because that reflects the number of times they've passed on their genes. So the researchers recorded how many children the women in these villages had given birth to. They also took various physiological measurements and analyzed the women's DNA.

They found that the women who bore the most children carried typical levels of hemoglobin — the blood responsible for transporting oxygen. But their hemoglobin was capable of carrying more oxygen than women who had fewer children.

Furthermore, the women with more children had greater blood flow to their lungs. And their left ventricles — the chamber of the heart that pumps oxygenated blood to the body — were wider than those with fewer children. A wider ventricle means more oxygen-rich blood can get to a person's tissues in a given heartbeat.

In a separate analysis, the researchers found that around 80% of the women in the study carried a version of a gene known as EPAS1, which is thought to lower hemoglobin concentrations in the blood. This may seem counterintuitive as having less hemoglobin means you can't carry as much oxygen in the blood. However, too much hemoglobin can thicken the blood, making people vulnerable to developing a condition known as chronic mountain sickness.

The fact that the EPAS1 variant is so common suggests there is a lot of pressure for this version of the gene to be passed on from one generation to the next.

These new findings shed light on how evolution and adaptation occurs in humans, study co-author Cynthia Beall, a professor emerita of anthropology at Case Western Reserve University in Ohio, told Live Science. The findings may also have applications in medicine — for instance, they could potentially provide insight into diseases that are associated with low oxygen levels, such as asthma and other lung conditions, she suggested.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

A common screening test for endometrial cancer may not be reliable in Black patients, a new study finds. 

The test, which uses ultrasound, is used to see whether or not a patient might need more invasive testing, involving a biopsy. Past research suggested that the ultrasound is very accurate for triaging patients in this way — but now, the new study suggests it may miss a concerning number of Black patients.

"This is a very important study," Dr. Christina Annunziata, a senior vice president of the American Cancer Society who was not involved in the research, told Live Science. 

The study, published June 27 in the JAMA Oncology, reveals one factor that might help explain why Black patients with endometrial cancer tend to be diagnosed later and suffer worse outcomes than other populations.

Related: 'Racism is a global public health crisis': Author Layal Liverpool says racist ideas still pervade medicine, and that hurts all of us 

Endometrial cancer, which affects the lining of the uterus, is the most common cancer of the female reproductive organs diagnosed in the United States, affecting more than 65,000 people a year. The disease mainly affects women over age 60, but the incidence of endometrial cancer has been rising for women of all ages for the past two decades.

That rate is increasing more rapidly for Black women than for women of other races. In addition, evidence shows Black women in the U.S. are at least twice as likely to die from certain subtypes of endometrial cancer than white women are. 

"One of the things that we know drives that disparity is that Black women are more likely to be diagnosed at later stages of the disease and are more likely to experience delays in diagnosis," Dr. Kemi Doll, lead author of the new study and a gynecologic oncologist at the University of Washington Medicine, told Live Science. 

One early marker of endometrial cancer is postmenopausal bleeding, meaning vaginal bleeding that occurs a year or more after a person's final period. When patients experience this symptom, doctors perform an ultrasound in the vagina to look closely at the pelvic area. If the thickness of the uterine lining passes a certain threshold, the patient will then receive a follow-up biopsy. Below this thickness, no further testing is typically done.  

"Those [thickness] thresholds are supposed to be 99% to 100% accurate," Doll said. "They should never miss endometrial cancer." Current standards dictate that people with a uterine lining thickness of 0.15 inch (4 millimeters) or greater should get a biopsy.

However, Doll grew suspicious of this test's sensitivity after she and colleagues uncovered in past work that Black women were less likely than white women to receive a biopsy after experiencing postmenopausal bleeding. In another study, she found that Black women who were screened were eight times likelier than white women to have a false-negative result, meaning the test indicated there wasn't cancer when there actually was.

In their new study, Doll and her colleagues probed this trend further by looking specifically at Black patients. They evaluated medical records from nearly 1,500 insured Black patients who had been treated in 10 hospitals in the southeastern U.S. These patients included six gender-expansive individuals, including transgender men.

All the patients had received an ultrasound before undergoing hysterectomy, a surgical procedure to remove the uterus. After the procedure, 210 patients, all cisgender women, were found to have endometrial cancer.   

The study revealed that about 10% of the women with endometrial cancer had a uterine lining that fell below the typical threshold that would trigger a follow-up biopsy. If a cut-off of 0.1 inch (3 mm) was used instead, that percentage would have fallen to less than 4%.

Related: The 10 deadliest cancers, and why there's no cure

"This surprised me," Doll said. This ultrasound screening has generally been considered a reliable method to screen for endometrial cancer. 

The rate of false-negatives was similar among patients with fibroids, or noncancerous growths in the uterus, that could be spotted via ultrasound. However, the rate was slightly higher in patients whose scans showed only part of their uterine lining or who experienced pelvic pain, which may cause sonographers to cut scans short.   

Based on these findings, Doll recommended that Black patients with endometrial cancer symptoms should get a tissue biopsy, to avoid misdiagnosis.

"What we know is that for clinical trials, in general, we have under-representation of diverse population groups," said Marvella Ford, associate director of community outreach and engagement at the Medical University of South Carolina who was not involved in the study. "Unfortunately, when that happens, we don't know how well these techniques and approaches work on different population groups," she told Live Science.

Often, it's assumed people have delayed diagnoses because they're not getting care at all, Doll noted. "What my research has been showing over the years is that even Black women with insurance, who are going to the doctor, are seemingly continuing to get advanced stage diagnoses." The insensitivity of screening tests may help explain that. 

Black women also tend to have higher rates of irregular bleeding prior to menopause than other groups do. This irregular bleeding may be misattributed to fibroids, which disproportionately affect Black women, instead of endometrial cancer, Doll said. This may further delay screening.

"If you have any sort of abnormal uterine bleeding, any sort of postmenopausal bleeding or bleeding in between menstrual periods, that is a reason to get screened for cancer," Annunziata stressed.

Doll hopes to further expand the study to better characterize the risk of false diagnosis beyond cisgender women.

"That's going to be increasingly important," she said. "And we continue to want to investigate 'why is this happening?'"

This article is for informational purposes only and is not meant to offer medical advice.

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Pregnancy places a lot of extra strain on the body, requiring more food than usual over the course of nine months to support the pregnancy and the growing baby. 

But exactly how many calories does it take to grow a baby?

It turns out that estimates range widely — from about 50,000 to nearly 85,000 extra calories over the course of an entire pregnancy. Those are additional calories on top of what that person would need if they weren't pregnant.

"I would say that, for most women, 50,000 calories is going to be a gross underestimate," said Herman Pontzer, a professor of evolutionary anthropology and global health at Duke University. "I think, for most, it's going to be more like 70,000 … or even more."   

Related: How calories are calculated: The science behind your food

Scientists have arrived at these numbers using different methods. For instance, a 2024 study published in the journal Science devised a formula for calculating the calorific cost of pregnancy for many species across the animal kingdom.

The team was led by Samuel Ginther, who was a doctoral student at Monash University at the time of the study. The researchers worked out the reproductive cost of 81 species, ranging from microscopic, aquatic animals to large mammals, including humans.

"We calculated that a pregnant person would require an additional 50,000 kcal [calories] over a 9-month period compared to a similar non-pregnant female over the same time period," Ginther told Live Science via email.

Of the 50,000 extra calories needed in pregnancy, the team estimated that just 4% go directly into growing the cells of the fetus. The majority are instead used to support the pregnant person's body as it changes throughout pregnancy, said Pontzer, who was not involved in the study.

"Fundamentally, energy expenditure is all about all of your cells doing their jobs all day," Pontzer said. "In pregnancy — when the body grows something around 12 kilos [26 pounds] in a normal pregnancy — all that extra tissue [is] all extra cells that weren't there before. And they've all got to do their jobs."

The energy demands of pregnancy change over the course of the nine months. The first trimester takes the least amount of added energy, according to a 2005 paper in the journal Public Health Nutrition. During this time, the weight gain for an average, healthy pregnant woman is around 0.6 ounce (18 grams) per day. This increases to 2.1 ounces (60 grams) per day during the second trimester and then decreases slightly to 1.9 ounces per day (54 grams) in the final trimester.

Related: Having a baby: Stages of pregnancy by trimester

The calories needed to support this extra tissue and grow a whole new human are likely higher than Ginther and colleagues' study suggests, Pontzer said.

"The real advancement in this new paper is that they've looked so broadly across the tree of life" — at reptiles, amphibians, fish and mammals, he said. "But we've known for a long time ­— thanks to groundbreaking work by Nancy Butte — that the energy costs of [human] pregnancy are upwards of 70,000 calories."

Butte, a professor of pediatrics and nutrition at Baylor College of Medicine, and her colleagues once published a meta-analysis of several studies that calculated the total energy cost of pregnancy. The figure came out to 77,675 calories. This would consist of an extra 90 calories per day in the first trimester, 287 calories per day in the second trimester and 466 calories per day in the third.

A review by a different group, published in 2019 in the journal Nutrients, looked over Butte's and others' work and concluded the needs of pregnancy ranged from 50 to 150 extra calories per day in the first trimester, 340 calories per day in the second and 452 calories per day in the third. Added up, that amounts to about 78,400 to 84,700 additional calories across the nine months. 

So, why are there discrepancies as to how many calories it takes to grow a baby?

"To give one number is going to be tough," Pontzer said. "A small woman is going to have probably a different energy cost than a big woman, just because we know that the energy cost of everything scales with size." Plus, the amount of energy needed also depends on how physically active a person is and other physiological traits, such as their metabolism.

But again, at least based on past research, Pontzer said, most pregnancies probably require well over 70,000 extra calories to sustain. 

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There's a common belief that women generally feel colder than men, but is that really backed by science?

Actually, the evidence is mixed, in part because few studies addressing this question have been conducted in a carefully controlled manner. That said, the data gathered to date suggest that people's perception of and ability to regulate body temperature rests not on their sex, but rather on their physical traits — in particular, their body fat and surface area. 

A lot of past research does seem to support the idea that women often feel colder than men. This has included survey-based studies that probed people's preferred thermostat temperatures in office settings. 

Research also suggests that, on average, women have slightly higher core temperatures than men, but their hands, feet and ears tend to be colder. This may be related to women's two main sex hormones: estrogen and progesterone. Estrogen dilates blood vessels in the extremities, allowing heat to escape; meanwhile, progesterone can constrict blood vessels in the skin, boosting core temperature but limiting blood flow to the extremities. 

Related: Has the average human body temperature always been the same?

This explanation hints at why women might feel colder than men — but again, there's likely more to the story. 

Several recent, well-designed studies have found that a person's body temperature regulation depends less on their sex and more on their physical traits. For example, in a small study published in the journal PNAS, scientists at the National Institutes of Health (NIH) found evidence that women and men perceive temperatures in a similar manner and don't show any major, sex-based bodily differences in how they respond to cold. 

"We tried to figure out what happens at the temperature at which people start to shiver — where they are cold but not fully overtly shivering," said lead study author Robert Brychta, an NIH staff scientist. 

In the study, 12 women and 16 men, all fairly lean, each stayed in a room as the scientists varied the temperature from hot to cool — roughly 88 degrees Fahrenheit (31 degrees Celsius) to about 63 F (17 C). The participants wore standardized outfits, as well as sensors that tracked electrical activity in their muscles and their skin temperatures.

A "calorimeter" measured the amount of oxygen people breathed and carbon dioxide they expelled; this helped the researchers track the amount of energy expended. People's weights, heights, body-fat percentages and basal metabolic rates were also recorded, as these factors affect heat production. 

Participants also rated their perception of the room temperature using a visual sliding scale from "very cold" to "very hot."

Men's and women's temperature perception was the same throughout the experiment, and they also shivered to the same extent at colder temperatures. The coldest temperature they could tolerate before shivering was the same, at about 68 F to 70 F (20 C to 21 C). 

The participants' skin temperatures were similar during the experiment, although, on average, women had slightly warmer skin than men did. Other physiological measurements — such as the electrical activity of their muscles — were also pretty much the same, but women's basal metabolic rates were slightly lower than men's.

Women did maintain slightly higher core body temperatures at cold temperatures than men did. This may be because the women, on average, had higher body fat percentages than men and thus more insulation, the researchers wrote in the paper. The temperature at which women's bodies started spending energy to stay warm — what the researchers called the lower-critical temperature — was also a touch lower than men's, by about 1.8 F (1 C), on average.

Taken together, the results suggest that women and men react to temperature changes in a similar way. Any differences you might observe from person to person rest on their individual differences in body composition.

"It is the interaction of the body surface area and the body fat percentage that contributes to where the lower-critical temperature falls," not a person's sex, Brychta told Live Science. "Though we see some differences between men and women, really, it's like an individualized point." For example, a taller woman with little body fat would likely have a warmer lower-critical temperature than a smaller man with more body fat.

The study led by Brychta and his colleagues was small in size, but it does start to challenge the notion that women always feel colder than men, writ large. 

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It's long been assumed that men were hunters and women were gatherers, but a new study reveals that both sexes have been equally adept at hunting in hunter-gatherer cultures.

An international team of scientists made the finding after examining data culled from dozens of academic papers, published over the past 100 years, that focused on 63 hunter-gatherer societies and burials of female hunters from around the world, including groups in North America, Africa, Australia and Asia, according to a study published Wednesday (June 28) in the journal PLOS One.

"We were reading papers written by people who had lived with these groups and had studied their behavior," study co-author Cara Wall-Scheffler, a professor and co-chair of biology at Seattle Pacific University, told Live Science. "They were looking at people and recording what they did."

Of the foraging communities assessed, 79% contained women who were hunters,  and their hunting status didn't shift once they became mothers. 

"The women would go out with many different tools — they had a very diverse tool kit all around the world — and if they saw an animal, they would kill it," Wall-Scheffler said. "We were surprised by how the majority of groups showed women hunting, and there was no explicit taboo against that." 

The researchers also noted that more than 70% of female hunting expeditions were classified as "intentional," meaning the women purposefully went out seeking meat, as opposed to engaging in opportunistic killings, in which they encountered animals while doing other tasks, such as foraging for plants, according to the study.

Most of these female hunters were "purposely hunting and going out to expressly hunt animals," Wall-Scheffler said. "We were surprised that it wasn't just opportunistic. Everyone in their community knew they would go hunting, and that was their job."

Related: 'Ghost footprints' left by ancient hunter-gatherers discovered in Utah desert

Furthermore, female hunters weren't hunting and trapping only small game, such as birds and rabbits. Rather, they were equal to male hunters when it came to big-game hunting in the Americas, making up roughly 50% of hunters targeting large animals such as deer and moose, according to the study.

"We reanalyzed the big-game burials from North and South America [in which people were buried with tools or animal bones], and prehistorically showed that women and men were 50/50 big-game hunters," Wall-Scheffler said.

So, who's to blame for the erroneous idea that men were hunters and women were gatherers?

Wall-Scheffler mentioned two books that likely helped solidify the idea: "Man the Hunter" (Aldine, 1968), based on a symposium of ethnographers, and a second book released 15 years later, titled "Woman the Gatherer" (Yale University Press, 1983).

"The purpose of [the second] book was to say, 'Fine, men are hunting, but actually, hunting is not a great way to bring in calories because it's very inconsistent,'" Wall-Scheffler said. "Because it's so inconsistent, males may be doing it — but they're not actually providing for the females, since females were bringing in their own food and they're totally fine because they were also always gathering.

But the books ended up creating "more rigid gender roles in which men were hunting and women were gathering and never the twain shall meet — and that has stuck around," she added. "It doesn't make sense that if something like hunting for animals would help feed their community, that women would ignore it. Having these rigid divisions of labor wouldn't make sense."

Female patients should start getting mammograms to screen for breast cancer at age 40 and then get one every other year, a U.S. panel of experts has recommended. Previously, the same panel advised that regular breast cancer screening should begin at age 50.

This new guidance was announced Tuesday (May 9) in a draft recommendation statement issued by the U.S. Preventive Services Task Force (USPSTF). The task force receives support from the U.S. Department of Health and Human Services, but it operates independently and is staffed by volunteer experts in primary care and prevention.

In previous guidance, issued in 2016, the task force recommended biennial breast cancer screenings for female patients ages 50 to 74 years old. Starting screening at younger ages, between 40 and 49 years old, was framed as an individual decision.

"New and more inclusive science about breast cancer in people younger than 50 has enabled us to expand our prior recommendation and encourage all women to get screened every other year starting at age 40," Dr. Carol Mangione, the Task Force's immediate past chair, said in the draft statement. The updated guidance also reflects improvements in digital mammography and in breast cancer treatment, which together have increased the benefits of getting mammograms earlier in life, Reuters reported.

Related: Hormonal birth control slightly increases breast cancer risk, regardless of type 

"This new recommendation will help save lives and prevent more women from dying due to breast cancer," Mangione said. (In its statement, the task force specified that it's using the term "women" to refer to cisgender women and other people assigned female at birth.) 

If all those eligible got the recommended screening, breast cancer mortality rates in the U.S. could drop by 19%, the USPSTF statement says. 

This general guidance applies to women at average risk for breast cancer, the statement says. It does not apply to people at high risk of the disease, such as those with a past history of breast cancer, those who carry certain genetic markers or those with a history of high-dose radiation therapy to their chest at a young age. Those individuals should consult a doctor about when to begin getting mammograms.

In the future, the task force hopes to issue recommendations tailored for specific racial groups, who face different levels of risk of early death from breast cancer, and for people with dense breast tissue, whose cancer may be difficult to detect on mammograms. The task force called for more research on both of these fronts.

A recent study suggested that Black patients should start undergoing mammograms at age 42, instead of 50, because their risk of breast cancer death in their 40s is higher than that seen in other racial groups. 

"Ensuring Black women start screening at age 40 is an important first step, yet it is not enough to improve the health inequities we face related to breast cancer," Dr. Wanda Nicholson, the task force vice chair, said in the statement. "In our draft recommendation, we underscore the importance of equitable followup after screening and timely and effective treatment of breast cancer and are urgently calling for more research on how to improve the health of Black women."

The task force is also calling for research on whether and how additional screening — with ultrasound or MRIs, for example — might help patients with dense breasts get diagnosed earlier.

The potential risks of getting mammograms include false-positive results — meaning a person's test results suggest they have cancer when they don't — which can lead to unnecessary biopsies and incorrect diagnoses, according to the Centers for Disease Control and Prevention (CDC). In addition, because mammograms involve X-ray exposure, each screening exposes patients to a small dose of ionizing radiation.  

"We all are exposed to ionizing radiation every day from the natural environment, but additional exposures can lead to an increase in the possibility of developing cancer later in life," the CDC states. The average dose of radiation used in a typical mammogram with two views of each breast is about 0.4 millisieverts (mSv); for context, U.S. citizens are exposed to about 3.11 mSv of "background radiation" in the environment each year.

"The benefits of breast cancer screening far exceed the radiation risks," the International Atomic Energy Agency states. 

Lower back tattoos may seem like an early 21st century fad popularized by low-rise-jeans clad celebrities, but new archaeological evidence from Egyptian mummies shows the practice is actually more than three millennia old. 

At the New Kingdom site of Deir el-Medina (1550 B.C. to 1070 B.C.), researchers Anne Austin and Marie-Lys Arnette have discovered that tattoos on ancient flesh and tattooed figurines from the site are likely connected with the ancient Egyptian god Bes, who protected women and children, particularly during childbirth. They published their findings last month in the Journal of Egyptian Archaeology.

Deir el-Medina lies on the western bank of the Nile, across from the archaeological site of Luxor. Beginning in 1922, around the same time that King Tut's tomb was found, the site was excavated by a French team. Known in the New Kingdom period as Set-Ma'at ("Place of Truth"), this was a planned community, a large neighborhood with rectangular gridded streets and housing for the workers responsible for building tombs for the Egyptian rulers. While the men would leave for days at a time to work on the tombs, women and children lived in the village of Deir el-Medina. An important feature of the site is the so-called Great Pit, an ancient dump full of pay stubs, receipts and letters on papyrus that have helped archaeologists better understand the lives of the common people.

Related: Ötzi the Iceman's tattoos may have been a primitive form of acupuncture

But nothing in the Great Pit mentions the practice of tattooing, so the discovery of at least six tattooed women at Deir el-Medina was surprising. "It can be rare and difficult to find evidence for tattoos because you need to find preserved and exposed skin," study lead author Anne Austin, a bioarchaeologist at the University of Missouri-St. Louis, told Live Science in an email. "Since we would never unwrap mummified people, our only chances of finding tattoos are when looters have left skin exposed and it is still present for us to see millennia after a person died."

The new evidence that Austin discovered came from two tombs that she and her team examined in 2019. Human remains from one tomb included a left hip bone of a middle-aged woman. On the preserved skin, patterns of dark black coloration were visible, creating an image that, if symmetrical, would have run along the woman's lower back. Just to the left of the horizontal lines of the tattoo is a depiction of Bes and a bowl, imagery related to ritual purification during the weeks after childbirth.

The second tattoo comes from a middle-aged woman discovered in a nearby tomb. In this case, infrared photography revealed a tattoo that is difficult to see with the naked eye. A reconstruction drawing of this tattoo reveals a wedjat, or Eye of Horus, and a possible image of Bes wearing a feathered crown; both images suggest that this tattoo was related to protection and healing. And the zigzag line pattern may represent a marsh, which ancient medical texts associated with cooling waters used to relieve pain from menstruation or childbirth, according to Austin.

In addition, three clay figurines depicting women's bodies that were found at Deir el-Medina decades ago were reexamined by study co-author Marie-Lys Arnette, an Egyptologist at Johns Hopkins University in Baltimore, who suggested that they too show tattoos on the lower back and upper thighs that include depictions of Bes.

The researchers concluded in their paper that "when placed in context with New Kingdom artifacts and texts, these tattoos and representations of tattoos would have visually connected with imagery referencing women as sexual partners, pregnant, midwives, and mothers participating in the post-partum rituals used for protection of the mother and child."

Sonia Zakrzewski, a bioarchaeologist at the University of Southampton University in the U.K. who was not involved in the current study, told Live Science in an email that "the newly described tattoos are extremely intricate relative to earlier Egyptian tattoo practices," and that "images of pregnant women are extremely rare in Egyptian art." Because childbirth and fertility of the soil were linked in Egyptian thought, Zakrzewski suggested that "these tattoos are imprinting protective representations — including of gods — on their body, almost like the person has their own portable magical amulet with them."

Tattooing in Deir el-Medina is even more common than people realized, according to Austin, though it is unknown how widespread it may have been elsewhere in Egypt during that period. "I'm hopeful more scholars will find evidence of tattooing so that we can see if what is happening in this village is unique or part of a broader tradition in ancient Egypt that we simply haven't discovered yet," she said.

Editor's note: This is story will continue to be updated. 

In 1973, the U.S. Supreme Court ruled on the landmark case of Roe v. Wade (410 U.S. 113 (1973)), in which seven of the nine sitting justices agreed that the Constitution protects the right to abortion. The case was initially raised to challenge a Texas law that banned all abortions except in the case that the pregnancy was deemed life-threatening to the patient, according to Oyez, a judicial archive maintained by the Illinois Institute of Technology's Chicago-Kent College of Law.

Although the court's ruling established a constitutional right to abortion that applied across the nation, it still allowed states to impose regulations on abortions in the second trimester and even prohibit the procedure in the third trimester, under certain circumstances. 

In a case called Planned Parenthood v. Casey (505 US 833 (1992)) that took place in 1992, the Supreme Court upheld the core decisions made in Roe but stated that state restrictions on abortion are unconstitutional if they place "undue burden" on the person seeking the procedure, according to Oyez. This ruling still forbid states from banning the majority of abortions, but it broadened the states' power to regulate the procedure.

On June 24, 2022, the Supreme Court overturned Roe v. Wade in a 6-3 ruling and thus eliminated the constitutional right to abortion.

Related: Is a 'fetal heartbeat' really a heartbeat at 6 weeks?

Who was Jane Roe?

In 1970, a woman living in Texas — referred to by the pseudonym "Jane Roe" in court documents — filed a lawsuit against Henry Wade, the district attorney of Dallas County, according to Oyez. 

After the case's conclusion, several news outlets reported that the plaintiff was Norma McCorvey, a Texas woman in her early 20s; McCorvey later came forward and confirmed these reports, according to the LA Times.  

McCorvey sought an abortion in Texas in 1969 after she'd become pregnant for the third time. The child that resulted from her first pregnancy was adopted and raised by McCorvey's mother, and the second child was adopted by another family, according to the LA Times. McCorvey was denied an abortion for her third pregnancy because, at the time, a Texas law made abortions a crime, except in the case that the pregnancy was deemed life-threatening by a doctor. 

Other Texas laws allowed abortions in the case of rape or incest, so at the time, McCorvey's friends suggested that she claim her pregnancy was a result of rape, but she'd had no means to back such a claim, according to the National Constitution Center.

McCorvey then sought to have an illegal abortion but was unsuccessful. Several months into her pregnancy, she met attorneys Linda Coffee and Sarah Weddington, who were building a case to challenge anti-abortion laws in Texas. McCorvey agreed to be the plaintiff in a lawsuit they filed against the district attorney of Dallas County, where McCorvey lived. The case would later be appealed to the U.S. Supreme Court, according to the LA Times. 

McCorvey carried out her pregnancy and delivered her baby before the first arguments were presented in the highest court of law. Her child was born in a Dallas hospital in 1970 and then placed for adoption, according to History. 51 years later, in 2021, a woman named Shelley Lynn Thornton came forward as the "Roe baby," The Atlantic reported. 

McCorvey died in 2017 at age 69, The New York Times reported. 

Details of the case

The initial suit in Texas was filed on behalf of McCorvey and all the other women "who were or might become pregnant and want to consider all options," according to History. The plaintiff argued that the Texas abortion laws were "unconstitutionally vague and abridged her right of personal privacy, protected by the First, Fourth, Fifth, Ninth, and Fourteenth Amendments," according to Oyez.

The U.S. District Court for the Northern District of Texas ruled in favor of McCorvey, stating that, yes, the Texas law was unconstitutional because it violated the right to privacy covered in the Ninth Amendment, according to the National Constitution Center.

(The Ninth Amendment states that "the enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people." Broadly speaking, that means that citizens aren't restricted to only rights listed in the Constitution; unlisted rights still belong to the citizens.)

Texas appealed the court's decision to the Supreme Court in 1970, and the initial arguments were heard in December 1971 and the case was reargued in October 1972. Finally, the court decided the case on Jan. 22, 1973, ruling 7-2 in favor of Roe, according to Oyez. 

Earlier court cases had drawn on language in the First, Fourth, Ninth, and Fourteenth Amendments to argue that citizens have certain "zones of privacy," according to the National Constitution Center. These zones of privacy covered activities such as contraception, marriage and child rearing. For example, in 1965, the Supreme Court used this justification to overturn a law banning the distribution of birth control to married couples, and in 1972, on a similar premise, it struck out a law forbidding the distribution of contraceptives to unmarried adults, according to History.

In Roe v. Wade, the justices deemed that these zones of privacy are "broad enough to encompass a woman’s decision whether or not to terminate her pregnancy," according to the National Constitution Center. 

In its decision, the court stated that states could not regulate any abortions in the first trimester, stating that only the patient and their doctor could be involved in that decision. However, the state may regulate abortions in the latter two trimesters, for the sake of protecting the pregnant person's health and "protecting the potentiality of human life." 

"In the second trimester, the state may impose regulations on abortion that are reasonably related to maternal health," accoridng to Oyez. "In the third trimester, once the fetus reaches the point of 'viability,' a state may regulate abortions or prohibit them entirely, so long as the laws contain exceptions for cases when abortion is necessary to save the life or health of the mother." 

In 1992, the court's ruling on the Planned Parenthood of Southeastern Pennsylvania v. Casey case adjusted this trimester framework. This later case affirmed that citizens hold a constitutional right to abortion under the Fourteenth Amendment and said that the right may not be unduly interfered with prior to the fetus reaching "viability," according to the National Constition Center.  

In this context, to place an "undue burden" on a woman seeking abortion is to introduce a "substantial obstacle in the path of a woman seeking an abortion before the fetus attains viability," Oyez states.

Originally published on Live Science.

From the beginning, women have made significant contributions to the fields of mathematics and science. But despite the fact that these pioneering women have changed the way we live in and think about the world, you might not be familiar with their names and faces. From the first woman to earn a Nobel Prize to a legendary primatologist, here are 30 amazing women who changed math and science forever.

Donna Strickland (Born in 1959)

Donna Strickland won the Nobel Prize in physics in 2018 for her role in developing a "method of generating high-intensity, ultra-short optical pulses," according to the Nobel Foundation. She was born in Guelph, Ontario, and dove into the world of laser and electro-optics while a student at McMaster University. In 1985, while getting her doctorate at the University of Rochester in New York, Strickland and French physicist Gérard Mourou created ultrashort, high-intensity laser pulses known as chirped pulse amplification (CPA), which has a variety of uses, including in corrective eye surgeries such as LASIK.

With CPA, laser pulses are stretched in time, amplified and compressed. This enables the pulse to be squished in time, and thus made shorter, so the same amount of light is stuffed into a tiny space and its intensity skyrockets.

"It took me a year to build the laser," Strickland wrote in an op-ed. "We proved that we could increase laser intensity by orders of magnitude. In fact, CPA led to the most intense laser pulses ever recorded. Our findings changed the world's understanding of how atoms interact with high-intensity light."

Strickland shared the 2018 prize with Mourou and physicist Arthur Ashkin for his work on optical tweezers, or laser beam "fingers" that could grasp particles, atoms, molecules and even living cells. At the time, she was the first woman in 55 years to win the Nobel Prize in physics. Moreover, she was only the third woman ever to win the Nobel Prize in physics, with the other two being Marie Curie in 1903 and Maria Goeppert-Mayer in 1963.

Rosalind Franklin (1920-1958)

Rosalind Franklin's work was key in determining the double helix shape of DNA, but she died before the Nobel Prize in physiology or medicine was awarded to men who used her work without her permission.

Franklin grew up in pre-World War II London. She attended a private girls school known for its rigorous academics. "She was best in science, best at maths, best in everything. She expected that if she undertook to do something, she would be in charge of it," two of her school friends said in an interview with PBS' "Nova" in an episode called "The Secret of Photo 51."

As a teenager, Franklin decided to be a scientist even though her father wanted her to go into social work. She got a doctorate in physical chemistry from the University of Cambridge in 1945. After working at a lab in Paris, Franklin moved to King's College London, where she had to leave for lunch every day because women were not permitted to eat in the college's cafeteria.

At King's College London, she used X-ray crystallography to take pictures of DNA and noted that one type of these images showed a helical structure with two visible strands. She called this image Photo 51. However, Franklin clashed with the lab's senior scientist, Maurice Wilkins, who called her the "Dark Lady," so she left for Birkbeck College (now called Birkbeck, University of London). During her move, Wilkins found Photo 51 and shared it with James Watson and Francis Crick, who later shared the Nobel Prize with Wilkins for determining DNA's double helix structure.

Franklin died in 1958 of ovarian cancer. It's possible her cancer was caused by her exposure to radiation during her X-ray crystallography work.

Jennifer Doudna (Born in 1964)

Biochemist Jennifer Doudna won the Nobel Prize in chemistry in 2020 alongside her collaborator Emmanuelle Charpentier. The two Nobel laureates helped usher in the age of CRISPR gene editing with a groundbreaking paper published in 2012. They're credited with transforming an immune system seen in bacteria into a highly precise tool that can snip specific bits of DNA from the genome. That tool, known by the shorthand CRISPR, has since been used to develop paradigm-shifting treatments for genetic disease, and its applications stretch beyond medicine, into basic research and agriculture.

Born in 1964 in Washington, D.C., Doudna now works at the University of California, Berkeley as a professor of biochemistry, biophysics and structural biology. She's the founder of the Innovative Genomics Institute, an interdisciplinary effort aimed at advancing genome engineering; educating the public about the emerging technology; and driving discussion of how to use it ethically. Doudna also co-founded and serves on the advisory panel of several companies that use CRISPR tech.

Sally Ride (1951-2012)

Astronaut Sally Ride became the first American woman in space when she blasted off on June 18, 1983, on the Challenger STS-7.

Ride was born in Los Angeles; in school, she enjoyed math as well as sports. She earned a full scholarship to Swarthmore College in Pennsylvania, where she became a women's college tennis champion. Because women's sports were not well supported at Swarthmore, Ride returned home to California, determined to be a professional tennis player. But once there, she ultimately transferred to Stanford University and completed bachelor's degrees in physics and English literature, followed by a master's degree and a doctoral degree in physics.

Ride joined NASA in 1978 after completing her studies at Stanford. She spent five years training for her first mission, which involved deploying communications satellites and doing scientific experiments in space. Her second shuttle mission was to help deploy the Earth Radiation Budget Satellite. During her time at NASA, Ride helped develop Canadarm, the space shuttle's robotic arm. In total, she spent more than 343 hours in space.

Following her work at NASA, in 1989, Ride joined the faculty of the University of California, San Diego, as a physics professor and director of the California Space Institute, where her research involved studying nonlinear optics and Thomson scattering, which deal with the measurement and behavior of light.

Ride led several public outreach projects for NASA over the years and created a company called Sally Ride Science, which launched science programs and publications aimed at middle-school girls. She co-authored seven books on space to encourage kids to study science.

After her death in 2012, Ride received the Presidential Medal of Freedom from Barack Obama in 2013. In 2018, Ride was featured on a first-class U.S. postage stamp, and in 2022, she was honored in the American Women quarters series, becoming the first known LGBTQ+ person to appear on U.S. currency.

Katherine Johnson (1918-2020)

American mathematician Katherine Johnson was a "human calculator" who was instrumental in the success of the early U.S. space program. As part of a team of African American women now lauded as "Hidden Figures" in the space industry, Johnson calculated orbital mechanics for the National Advisory Committee for Aeronautics (NACA) — the predecessor of NASA — that helped put the first Americans in space.

According to NASA, Johnson calculated the trajectory for Alan Shepard, the second human and first American astronaut to reach space, in 1961. Later, after NASA began using digital computers, astronaut John Glenn requested that Johnson personally check the machine's calculations before his flight aboard Friendship 7, in which he became the first American to orbit Earth.

Johnson was born in 1918 in the small town of White Sulphur Springs, West Virginia. Fascinated by math, she started high school at the age of 10 and graduated college at 18. After years of teaching, she joined NACA as a "computer" in 1953 and continued to work for the agency, which would later become NASA, until 1986. She died in February 2020 at the age of 101, after being awarded the Presidential Medal of Freedom by Barack Obama in 2015 and receiving numerous other awards from NASA and the U.S. government. She was portrayed by Taraji P. Henson in the 2016 film "Hidden Figures" and received a standing ovation when she appeared beside Henson onstage at the 89th Academy Awards.

Mary Anning (1799-1847)

Mary Anning was a self-taught fossil hunter. She was born and raised near the cliffs of Lyme Regis in southwestern England; the rocky outcrops near her home were teeming with Jurassic fossils.

She taught herself to recognize, excavate and prepare these relics when the field of paleontology was in its infancy — and closed to women. Anning provided London paleontologists with their first glimpse of an ichthyosaur, a large marine reptile that lived alongside dinosaurs, in fossils that she discovered when she was no more than 12 years old, the University of California Museum of Paleontology (UCMP) in Berkeley, California, reported. She also found the first fossil of a plesiosaur (another extinct marine reptile). To honor Anning, scientists named a new species of ichthyosaur (Ichthyosaurus anningae) after her in 2015.

Maria Sibylla Merian (1647-1717)

Entomologist, botanist, naturalist and artist Maria Sibylla Merian created extraordinarily detailed and highly accurate drawings of insects and plants. By working with live specimens, Merian noted and revealed aspects of biology that were previously unknown to science.

Prior to Merian's investigations of insect life and her discovery that insects hatched from eggs, it was widely thought that the creatures generated spontaneously from mud. She became the first scientist to observe and document not only insect life cycles but also how the creatures interacted with their habitats, The New York Times reported in 2017.

Merian's best-known work is the 1705 book "Metamorphosis Insectorum Surinamensium," a compilation of her field research on the insects of Suriname, according to the Royal Collection Trust in the U.K.

Sylvia Earle (born 1935)

Marine biologist and oceanographer Sylvia Earle takes an immersive approach to ocean science; she is affectionately known as "Her Deepness," from the title of a 1989 profile in The New Yorker. In nearly 70 years of diving, beginning when she was 16 years old, Earle has cumulatively spent about a year underwater, she told The Telegraph in 2017.

Earle began her ocean research in the late 1960s. In 1968, she was the first woman scientist to descend in a submersible to a depth of 100 feet (31 meters) in the Bahamas, and she did so while she was four months pregnant, The Telegraph reported.

Related: In Images: Sylvia Earle's 'Searching for Wisdom' Expedition

Two years later, Earle led a team of five women "aquanauts" on a two-week mission exploring the seafloor, in the underwater laboratory Tektite II. Since then, Earle has led more than 100 expeditions in oceans around the world, and in 1990, she became the first woman to serve as chief scientist of the National Oceanic and Atmospheric Administration (NOAA).

Mae Jemison (born 1956)

In 1992, when the space shuttle Endeavour blasted off, NASA astronaut Mae Jemison became the first African American woman to reach space. But astronaut is just one of her many titles. Jemison is also a physician, a Peace Corps volunteer, a teacher, and a founder and president of two technology companies, according to Space.com, a Live Science sister site.

Jemison was born in Decatur, Alabama, on Oct. 17, 1956. When she was 3 years old, she moved with her family to Chicago. At age 16, the aspiring scientist attended Stanford University, where she earned degrees in chemical engineering and African and African American studies. She got her doctorate in medicine from Cornell University in New York state in 1981.

After training with NASA, Jemison and six other astronauts orbited Earth 126 times on the Endeavour. During her 190 hours in space, Jemison helped carry out two experiments on bone cells.

Jemison is also a polyglot, speaking English, Russian, Japanese and Swahili, and she even has a Lego minifigure made in her honor.

Maria Goeppert Mayer (1906-1972)

In 1963, theoretical physicist Maria Goeppert Mayer became the second woman to win a Nobel Prize in physics, 60 years after Marie Curie won the award.

Goeppert Mayer was born on June 28, 1906, in Kattowitz, Germany (now Katowice, Poland). Although women from her generation rarely attended university, Goeppert Mayer went to the University at Göttingen in Germany, where she plunged into the relatively new and exciting field of quantum mechanics.

By 1930, at age 24, she had earned her doctorate in theoretical physics. She married the American Joseph Edward Mayer and moved with him so he could work at Johns Hopkins University in Baltimore. The university wouldn't employ her, given that it was the Depression, but she continued working on physics anyway.

When the couple moved to Columbia University in New York, she worked on the separation of uranium isotopes for the atomic bomb project, according to Britannica. Her later research at the University of Chicago on the architecture of nuclei — how different orbital levels held different components of the nucleus in atoms — won her a Nobel Prize that she shared with two other scientists.

Rita Levi-Montalcini (1909-2012)

Rita Levi-Montalcini's father discouraged her from pursuing a higher education, because he held Victorian notions and thought that women should embrace the full-time job of being a wife and mother. But Levi-Montalcini pushed back, and eventually, her work on nerve growth factor would earn her the Nobel Prize in physiology or medicine.

The road to success was not easy. Born in Italy in 1909, Levi-Montalcini made it to medical school, where she graduated summa cum laude in medicine and surgery in 1936. Then, she began to study neurology and psychiatry, but her research was interrupted by World War II. Undeterred, she set up a research lab in her home, where she studied development in chick embryos until she had to abandon her work and go into hiding in Florence, Italy.

After the war, she accepted a position at Washington University in St. Louis, where she and her colleagues found that a substance from a mouse tumor spurred nerve growth when it was put into chick embryos. Her lab colleague Stanley Cohen was able to isolate the substance, which the two researchers called nerve growth factor. He shared the Nobel Prize with Levi-Montalcini in 1986.

Maryam Mirzakhani (1977-2017)

Maryam Mirzakhani was a mathematician known for solving hard, abstract problems in the geometry of curved spaces. She was born in Tehran, Iran, and did her most important work as a professor at Stanford University, between 2009 and 2014.

Her work helped explain the nature of geodesics, straight lines across curved surfaces. It had practical applications for understanding the behavior of earthquakes and turned up answers to long-standing mysteries in the field.

In 2014, she became the first — and still only — woman to win the Fields Medal, the most prestigious prize in mathematics. Each year, the Fields Medal is awarded to a handful of mathematicians under the age of 40 at the International Mathematical Union's International Congress of Mathematicians.

Mirzakhani received her medal one year after she was diagnosed with breast cancer, in 2013. She died from cancer on July 14, 2017, at age 40. Mirzakhani continues to influence her field, even after her death; in 2019, her colleague Alex Eskin won the $3 million Breakthrough Prize in mathematics for revolutionary work he did with Mirzakhani on the "magic wand theorem." Later that year, the Breakthrough Prize endowed a new award in Mirzakhani's honor that would go to promising young female mathematicians.

Emmy Noether (1882-1935)

Emmy Noether was one of the great mathematicians of the early 20th century, and her research helped lay the groundwork for both modern physics and two key fields of mathematics.

Noether, a Jewish woman, did her most important work as a researcher at the University of Göttingen in Germany between the late 1910s and early 1930s.

Her most famous work is called Noether's theorem, which has to do with symmetry; it laid the groundwork for further work that became necessary for modern physics and quantum mechanics.

Later, she helped build the foundations of abstract algebra — the work for which she is most highly regarded among mathematicians — and made foundational contributions to a number of other fields.

In April 1933, Adolf Hitler expelled Jews from the universities. For a time, Noether saw students in her home, before following other Jewish German scientists, like Albert Einstein, to the United States. She worked at both Bryn Mawr College in Pennsylvania and Princeton University before dying in April 1935.

Susan Solomon (born 1956)

Susan Solomon is an atmospheric chemist, author and professor at the Massachusetts Institute of Technology who for decades worked at NOAA. During her time at NOAA, she was the first to propose, with input from her colleagues, that chlorofluorocarbons (CFCs) were responsible for the Antarctic hole in the ozone layer.

She led a team in 1986 and 1987 to McMurdo Sound on the southern continent, where the researchers gathered evidence that the chemicals, released by aerosols and other consumer products, interacted with ultraviolet light to remove ozone from the atmosphere.

This led to the U.N. Montreal Protocol, which went into effect in 1989, banning CFCs worldwide. It is considered one of the most successful environmental projects in history, and the hole in the ozone layer has shrunk considerably since the protocol's adoption.

Virginia Apgar (1909-1974)

Dr. Virginia Apgar was a pioneer in the medical fields of anesthesiology and obstetrics, best known for her invention of the Apgar score, a simple and quick method to assess the health of newborns.

Apgar received her medical degree in 1933 and planned to become a surgeon. But there were limited career opportunities for women in surgery at the time, so she switched to the emerging field of anesthesiology. She would go on to become a leader in the field and the first woman to be named a full professor at Columbia University's College of Physicians and Surgeons, according to the National Institutes of Health.

One of Apgar's areas of research investigated the effects of anesthesia used during childbirth. In 1952, she developed the Apgar scoring system, which assesses the vital signs of newborns in the first minutes of life. The score is based on measures of the newborn's heart rate, breathing effort, muscle tone, reflexes and color, with lower scores indicating that the baby needs immediate medical attention. The system reduced infant mortality and helped give rise to the field of neonatology, and it is still used today.

Brenda Milner (born 1918)

Sometimes called the "founder of neuropsychology," Brenda Milner has made groundbreaking discoveries about the human brain, memory and learning.

Milner is best known for her work with "Patient H.M.," a man who lost the ability to form new memories after undergoing brain surgery for epilepsy. Through repeated studies in the 1950s, Milner found that Patient H.M. could learn new tasks, even if he had no memory of doing it. This led to the discovery that there are multiple types of memory systems in the brain, according to the Canadian Association for Neuroscience. Milner's work played a major role in the scientific understanding of the functions of different areas of the brain, such as the role of the hippocampus and frontal lobes in memory and how the two brain hemispheres interact.

Her work continues to this day. At age 104, Milner is still a professor in the Department of Neurology and Neurosurgery at McGill University in Montreal, according to the Montreal Gazette.

Karen Uhlenbeck (born 1942)

In 2019, American mathematician Karen Uhlenbeck became the first woman to receive the Abel Prize, one of the most prestigious math awards. Uhlenbeck won for her groundbreaking contributions to mathematical physics, analysis and geometry.

She is considered one of the pioneers in the field of geometric analysis, which is the study of shapes using partial differential equations (the derivatives, or rates of change, of multiple different variables, often labeled x, y and z). And the methods and tools that she developed are being used widely throughout the field.

Related: The 11 Most Beautiful Mathematical Equations

Uhlenbeck made major contributions to gauge theories, a set of quantum physics equations that define how subatomic particles should behave. She also figured out the shapes that soap films can take in higher-dimensional curved spaces.

About the Abel Prize, her longtime friend Penny Smith, a mathematician at Lehigh University in Pennsylvania, said, "I can't think of anyone who deserves it more. ... She really is not just brilliant but creatively brilliant, amazingly creatively brilliant."

Jane Goodall (1934-2025)

Jane Goodall was a legendary primatologist whose work with wild chimpanzees changed the way we see these animals and their relationship with humans.

In 1960, Goodall began her study of chimpanzees in the Gombe forest of Tanzania. Immersing herself with the animals, she made several revolutionary discoveries, including that chimpanzees make and use tools — a trait that was previously thought to be uniquely human, according to National Geographic. She also found that the animals displayed complex social behaviors, such as altruism and ritualized behaviors, as well as gestures of affection.

In 1965, Goodall earned a doctorate in ethology from the University of Cambridge, becoming one of only a handful of people ever allowed to study at the university at the graduate level without first receiving an undergraduate degree. In 1977, Goodall founded the Jane Goodall Institute to support research and protection of chimpanzees. Goodall died in October, 2025, at the age of 91.

Ada Lovelace (1815-1852)

Ada Lovelace was a 19th century self-taught mathematician and is thought of by some as the "world's first computer programmer."

Lovelace grew up fascinated by math and machinery. At age 17, she met English mathematician Charles Babbage at an event where he was demonstrating a prototype for a precursor to his "analytical engine," the world's first computer. Fascinated, Lovelace decided to learn everything she could about the machine.

In 1837, Lovelace translated a paper written about the analytical engine from French. Alongside her translation, she published her own detailed notes about the machine. The notes, which were longer than the translation itself, included a formula she created for calculating Bernoulli numbers. Some say that this formula can be thought of as the first computer program ever written.

Lovelace is now a major symbol for women in science and engineering. Her day is celebrated on the second Tuesday of every October.

Dorothy Hodgkin (1910-1994)

Dorothy Hodgkin, an English chemist, won the Nobel Prize in chemistry in 1964 for figuring out the molecular structures of penicillin and vitamin B12.

She became very interested in crystals and chemistry at age 10, and as an undergraduate at the University of Oxford, she became one of the first to study the structure of organic compounds using a method called X-ray crystallography. In her graduate studies at the University of Cambridge, she extended the work of British physicist John Desmond Bernal on biological molecules and helped to make the first X-ray diffraction study of the stomach enzyme pepsin, according to Britannica.

When she was offered a temporary research fellowship in 1934, she returned to Oxford, staying there until she retired. She established an X-ray lab at Oxford's Museum of Natural History, where she began her research on the structure of insulin.

In 1945, Hodgkin successfully described the arrangement of the atoms in penicillin's structure, and in the mid-1950s, she discovered the structure of vitamin B12. In 1969, nearly four decades after her first attempt, she determined the chemical structure of insulin.

Caroline Herschel (1750-1848)

Caroline Herschel, born in Hannover, Germany, in 1750, might owe her reputation as the world's first professional female astronomer to a bad case of typhus. At 10 years old, Caroline's growth was permanently stunted by the illness — her height peaked at 4 feet, 3 inches (130 centimeters), according to Britannica — as were her marriage prospects. Doomed to be an old maid, as far as her parents were concerned, Herschel's education was abandoned for housework, until her brother, William Herschel, spirited her away to Bath, England, in 1772.

William Herschel was a musician and astronomer, and he tutored his sister in both vocations. Eventually, Caroline Herschel graduated from grinding and polishing her brother's telescope mirrors to honing his equations and making celestial discoveries all her own. While assisting her brother in his role as court astronomer to King George III in 1783, Caroline Herschel detected three previously undiscovered nebulas; three years later, she became the first woman to discover a comet.

In 1787, the king awarded Caroline Herschel an annual pension of 50 pounds, making her the first professional female astronomer in history. She cataloged more than 2,500 nebulas before her death, in 1848, and was awarded gold medals from both the Royal Astronomical Society and the King of Prussia for her research.

Sophie Germain (1776-1831)

Sophie Germain was a French mathematician best known for her discovery of a special case in Fermat's last theorem that is now called Germain's theorem and for her pioneering work in the theory of elasticity.

Germain's fascination with math began when she was only 13 years old. As a young woman in the early 1800s, Germain's interest in science and mathematics was not well received by her parents, and she was not allowed to receive a formal education in the subject.

So Germain studied behind her parents' back at first and used a male student's name to submit her work to the math instructors she admired. The instructors were impressed, even when they found out that Germain was a woman, and they took her under their wing as much as they could at the time, according to Louis L. Bucciarelli and Nancy Dworsky's book "Sophie Germain: An Essay in the History of the Theory of Elasticity" (Springer Netherlands, 1980).

In 1816, Germain won a contest to come up with a mathematical explanation for a set of unusual images created by German physicist Ernst Chladni. It was Germain's third try to solve the puzzle, which she did by correcting her previous errors. Although her third solution still contained minor discrepancies, the judges were impressed and deemed it worthy of a prize.

Around 1820, Germain wrote to her mentors, Carl Friedrich Gauss and Joseph-Louis Lagrange, about how she was working to prove Fernat's last theorem, according to Agnes Scott College in Georgia. Germain's efforts eventually led to what is now known as Sophie Germain's theorem.

Patricia Bath (1942-2019)

Dr. Patricia Bath was an American ophthalmologist and laser scientist. Bath became the first female ophthalmologist to be appointed to the faculty of the University of California, Los Angeles (UCLA) School of Medicine Jules Stein Eye Institute, in 1974; the first woman to chair an ophthalmology residency program in the United States, in 1983; and the first female African American physician to receive a patent for a medical invention, in 1986.

Bath was inspired at a young age to pursue a career in medicine after learning of Dr. Albert Schweitzer's service to the people of what is now Gabon, in Africa, in the early 1900s, according to the U.S. National Library of Medicine.

While completing her medical training in New York City in 1969, Bath noticed that there were far more blind or visually impaired patients at the eye clinic in Harlem compared with the eye clinic at Columbia University. So she conducted a study and found that the prevalence of blindness in Harlem was a result of the lack of access to eye care. To solve the problem, Bath proposed a new discipline, community ophthalmology, which trains volunteers to offer primary eye care to underserved populations. The concept is now employed worldwide and has saved the sight of thousands who would have otherwise gone undiagnosed and untreated.

As a new female and Black faculty member at UCLA, Bath experienced numerous instances of sexism and racism. In 1977, she co-founded the American Institute for the Prevention of Blindness, an organization whose mission is to protect, preserve and restore sight.

Bath's research on cataracts led to her invention of a new method and device to remove cataracts, called the laserphaco probe. She earned a patent for the technology in 1986. Today, the device is used worldwide.

Rachel Carson (1907-1964)

Rachel Carson was an American biologist, conservationist and science writer. She is best known for her book "Silent Spring" (Houghton Mifflin, 1962), which describes the harmful effects of pesticides on the environment. The book eventually led to the nationwide ban of DDT and other harmful pesticides, according to the National Women's History Museum.

Carson studied at the Woods Hole Oceanographic Institution in Massachusetts and received her master's degree in zoology from Johns Hopkins University in 1932. In 1936, Carson became the second woman hired by the U.S. Bureau of Fisheries (which later became the U.S. Fish and Wildlife Service), where she worked as an aquatic biologist, according to the U.S. Fish and Wildlife Service. Her research allowed her to visit many waterways around the Chesapeake Bay region, where she first began to document the effects of pesticides on fish and wildlife.

Carson was a talented science writer, and the Fish and Wildlife Service eventually made her the editor in chief of all its publications. After the success of her first two books on marine life, "Under the Sea Wind" (Simon and Schuster, 1941) and "The Sea Around Us" (Oxford, 1951), Carson resigned from the Fish and Wildlife Service to focus more on writing.

With the help of two other former employees from the Fish and Wildlife Service, Carson spent years studying the effects of pesticides on the environment across the United States and Europe. She summarized her findings in her fourth book, "Silent Spring," which spurred enormous controversy. The pesticide industry tried to discredit Carson, but the U.S. government ordered a complete review of its pesticide policy, and as a result, banned DDT. Carson has since been credited with inspiring Americans to consider the environment.

Ingrid Daubechies (born 1954)

The honors and scientific citations Ingrid Daubechies would make a CVS receipt look small: Daubechies, born in 1954 in Brussels, where she earned both her bachelor's and doctorate degrees in physics, was drawn to math from an early age. In addition to having an interest in how things worked, she also loved figuring out "why certain mathematical things were true (like the fact that a number is divisible by 9 if, when you add all its digits together, you get another number divisible by 9," she once said, according to a short bio on the website of the University of St. Andrews in Scotland. She also loved sewing doll clothes — because, of course, of math. "It was fascinating to me that by putting together flat pieces of fabric one could make something that was not flat at all, but followed curved surfaces." And she recalls falling asleep while computing powers of 2 in her head, according to the St Andrews bio.

Perhaps the most important number to her would be 1987. That was not just the year she got married but also when she made a major mathematical breakthrough in the field of wavelets; these are akin to "miniwaves," because rather than going on forever (think about sine and cosine), they quickly fade, with the wave heights starting at zero, rising and then quickly dropping back to zero.

She discovered so-called orthogonal wavelets (now called Daubechies wavelets), which are used in JPEG 2000 image compression and even in some models used for search engines.

Currently, she is a professor of mathematics and electrical and computer engineering at Duke University, where she studies wavelet theory, machine learning and other fields at the intersection of physics, math and engineering.

Marie Curie (1867-1934)

Marie Curie broke ground not only for becoming the first woman to win a Nobel Prize but also for being a remarkable scientist whose impact on the world was profound and long-lasting. She is remembered chiefly for her discovery of radium and polonium, and her contributions to the study of radioactivity.

But Curie is also known for a string of other achievements, according to the Nobel Prize website and Britannica. In 1903, for example, Curie became the first woman in France to earn a doctorate in physics. She was the first woman to become a professor at the University of Paris and teach classes at the Sorbonne. She pioneered the use of radium in treating cancer tumors. In 1911, she received a second Nobel Prize, this time in chemistry, in recognition of her work in radioactivity. She was also responsible for establishing the use of X-ray machines in World War I, and for creating two important medical institutes — one in Poland and one in France.

Born Marie Sklodowska in Warsaw, Poland, in 1867, she moved to Paris in 1891, where she met and married Pierre Curie, a French physicist with whom she shared (along with physicist Henri Becquerel) her first Nobel Prize. She studied at the University of Paris, earning her doctorate there in 1903. Despite working in relative obscurity during her early years, her work on radioactive substances gradually drew her national and international attention; by the end of her life, she was famed throughout the world and honored for her many achievements.

She died in 1934 because of illnesses brought on by her long exposure to radiation and was buried at the famous Panthéon in Paris.

Barbara McClintock (1902-1992)

Barbara McClintock was an American scientist whose trailblazing studies in cytogenetics — the study of chromosomes and their genetic expression — garnered her the 1983 Nobel Prize in physiology or medicine. Today, her theories, especially about "jumping genes," are fundamental to a precise understanding of genetics.

But McClintock almost missed out on pursuing a career as a scientist. Although she wanted to attend Cornell University, her mother was reluctant to send her there, fearing that the move would ruin her marriage prospects, according to the Nobel Prize website. McClintock's father, a physician, came to her rescue and allowed her to attend.

At Cornell, McClintock studied genetics, which, at the time, was a relatively new field of study and one that very few women pursued. She followed this area of study as she continued in her graduate and postgraduate years. She taught at the University of Missouri for a while before finding a permanent position as a researcher for Cold Spring Harbor Laboratory, a New York research facility funded by the Carnegie Institution.

McClintock's studies in genetics remain her greatest legacy. Her primary area of focus was looking at how genes controlled the color patterns of maize kernels. She discovered the ability of a DNA sequence to change position on a genome, causing traits to be "switched" on or off, according to a 2012 article in the journal Proceedings of the National Academy of Sciences. This idea came to be known as genetic transposition, or "jumping genes." The finding transformed ideas about genes, which, at the time, were considered unchangeable, stable entities that could only be passed along from generation to generation. But by the 1960s, the larger scientific community had validated her findings and observations.

Chien-Shiung Wu (1912-1997)

Chien-Shiung Wu was a Chinese American physicist famous for her work on weak subatomic interactions — the interactions responsible for radioactive decay. She was involved in the top-secret Manhattan Project during World War II, the American-led effort to develop the atomic bomb.

Wu was born in Liuhe, China, to parents who encouraged her scientific aspirations, according to the National Park Service. She excelled in math and science and attended National Central University, earning a degree in physics. She continued her studies at the University of California, Berkeley, finishing her doctorate in 1940. Rather than returning to China, Wu remained in the United States, taking teaching posts at Smith College and later at Princeton University, where she became the first female faculty member hired by the university.

With the advent of World War II, however, Wu received a position at Columbia University, which involved work on the Manhattan Project. Her research focused on producing bomb-grade uranium by identifying a process using gaseous infusion to separate uranium metal, according to the National Women's History Museum in Virginia. This was a crucial step toward transforming a bomb into an atomic bomb.

After the war, Wu remained at Columbia, eventually becoming the first woman to hold a tenured faculty position in the university's physics department. She retired in 1981 and died in New York City in 1997. In 2021, the U.S. Postal Service honored Wu by putting her on a postage stamp.

Melba Roy Mouton (1929-1990)

Melba Roy Mouton was an American mathematician and computer programmer who made groundbreaking contributions to NASA. Mouton received an Apollo Achievement Award for her part in the successful Apollo 11 moon landing on July 20,1969.

Mouton was born in 1929 in Fairfax, Virginia. She was a budding mathematical prodigy at school and went on to earn both a bachelor's and a master's degree in math from Howard University. She worked for the Army Map Service and the Census Bureau before moving to NASA in 1959. There, she first became head mathematician at the Goddard Space Flight Center and oversaw the team tracking satellites in orbit.

Two years later, Mouton joined the Mission and Trajectory Analysis Division as head programmer, where she was responsible for coding computer programs to track NASA spacecraft. She eventually became assistant chief of research programs for the Trajectory and Geodynamics Division at Goddard. Mouton retired in 1973 and died in 1990, at the age of 61, due to brain cancer.

In 2023, the International Astronomical Union named a gigantic 20,000-foot-tall (6,000 m) lunar mountain "Mons Mouton" in her honor. The feature is one of the 13 candidate landing regions for NASA's Artemis 3 mission, which aims to send astronauts — including the first woman and person of color — to the moon.

Alice Ball (1892-1916)

Alice Ball was an American chemist who, at 23 years old, pioneered a treatment for Hansen's disease, also known as leprosy, that remained in use until the 1940s. She was both the first woman and the first African-American to earn a master's degree from the University of Hawaii, and became the first female chemistry professor at the university.

Ball was born on July 24,1892, in Seattle, Washington. She earned degrees in chemistry and pharmaceutical chemistry from the University of Washington. She moved to Hawaii and completed her master's after writing a thesis on the chemical properties of chaulmoogra oil, a substance derived from the seeds of a tropical evergreen tree (Hydnocarpus wightianus), which was already being used to heal leprosy. At 23 years old, Ball revolutionized the treatment by creating a water-soluble solution that could be safely injected, known as the "Ball Method."

Ball fell ill shortly after making the discovery and died in 1916 of unknown causes. Arthur L. Dean, at the time the president of the University of Hawaii, continued her pioneering work and made the treatment widely accessible. He gave Ball no credit for the technique, however, and renamed it the "Dean Method."

Her name might have been lost to history but her thesis supervisor, Dr. Harry T. Hollmann, explicitly gave her the credit for the chaulmoogra solution in a 1922 medical journal. The University of Hawaii did not recognize Ball's achievements until 2000, when the institution finally placed a plaque in her honor under its only chaulmoogra tree and declared Feb. 29 Alice Ball day.

Originally published on March 8, 2020. Updated on March 18, 2022 by Tom Garlinghouse, March 7, 2023 by Sascha Pare, and Feb. 11, 2025 by Brandon Specktor, Kristina Killgrove, Laura Geggel and Nicoletta Lanese.

In the United States, the average life expectancy for women is 81 years, according to the Centers for Disease Control and Prevention (CDC). For men, it's 76 years. Around the world, women live longer, on average. So why do women tend to outlive men?

Two of the main causes are biological, said Virginia Zarulli, an associate professor of demography at the University of Southern Denmark. The first cause relates to differences in sex hormones, at least in cisgender people (people whose gender identity matches the biological sex they were assigned at birth). Cisgender women produce more estrogen and less testosterone than cisgender men do. Estrogen provides protection against a range of diseases, such as cardiovascular disease, according to a 2017 study in the journal Biology of Sex Differences. 

High levels of testosterone, on the other hand, have been linked to an increased risk of some diseases, such as endometrial and breast cancer in women and prostate cancer in men, according to a 2020 study in the journal Nature Medicine. Testosterone has also been linked to risky behavior and higher levels of aggression, which can increase the risk of dying at a younger age, Zarulli said.

Related: Is the Y chromosome dying out?

There's also a genetic component at play. Humans have two sex chromosomes: X and Y. Cisgender women have two X chromosomes, and cis men have an X and a Y. "If you think about that, the Y chromosome is an X chromosome with a missing leg. It's missing genetic material," Zarulli said. "Women have this double X chromosome — extra genetic material — which allows them to, for instance, have a backup plan if there is a bad mutation on one of the two X chromosomes. The other X can let them live anyway." This is the case for diseases such as hemophilia, a type of bleeding disorder, and Duchenne muscular dystrophy, which causes the muscles to progressively weaken.

This biological advantage gives women, on average, just under a year of longer life expectancy when they are young adults compared with men, according to a 2003 study published in the journal Population and Development Review on more than 11,000 Bavarian Catholic nuns and monks who lived between 1890 and 1995. In strict religious settings, men and women have similar lifestyles, and both sexes avoid risky behaviors; therefore, their difference in longevity is probably biological, Zarulli said. However, the study doesn't report on life expectancy from birth but from young adulthood, so the difference in total life expectancy is probably more. Zarulli said that biology gives women about two additional years of life, on average.

Additionally, when infants are in settings with particularly high mortality rates, such as during severe famines and epidemics and when they are enslaved, baby girls have higher survival rates than baby boys, according to a 2018 study led by Zarulli and published in the journal Proceedings of the National Academy of Sciences.

But, on average, women live four or five more years than men, Zarulli said. So what accounts for the rest of their survival advantage?

Social factors play a large role, she said. Men tend to smoke cigarettes and drink alcohol more often than women; men are nearly twice as likely to binge drink and are more likely to have had alcohol in the past 30 days, according to the CDC, and 35% of men in the world smoke compared with 6% of women, according to data from the World Bank. Women are more likely to trust in healthy nutrition and men are more likely to prefer fatty meals and eat fast food, according to a 2020 review study in the journal Advances in Clinical and Experimental Medicine. And women are 33% more likely to visit a doctor, excluding pregnancy-related care, than men are, according to a 2001 study by the CDC.

But it's impossible to completely tease apart biology and social effects to explain phenomena such as why men engage in riskier behaviors. "Both tend to influence the sex gap in life expectancy," Zarulli said. The interaction between the two is "impossible to divide," she said.

The life expectancy gap hasn't always been as wide as it is now. Detailed mortality records show that women didn't consistently live longer than men until about the start of the 20th century, according to a report from the National Bureau of Economic Research. Before then, infectious diseases ran rampant and hit both sexes fairly equally. In addition, women often died during childbirth.

Since then, women's life expectancy hasn't always risen as much as it could. Starting in the mid-1970s, the gap between potential and observed life expectancy started to increase for women due to cigarette smoking, according to a 2011 report by the National Research Council. By 2005, women were living, on average, 2.3 years less than expected because so many women had started smoking.

Originally published on Live Science.

Women who use marijuana while they are figuring out how to get pregnant may be less likely to get pregnant compared with those who don't get high, a new study suggests.

The study researchers found that, among women trying to get pregnant, those who reported using marijuana or who had a positive urine test for the drug were 40% less likely to get pregnant during each monthly cycle, compared with those who didn't use marijuana.

In addition, marijuana users had differences in levels of certain reproductive hormones, which could potentially affect their pregnancy chances.

"These results highlight potentially harmful associations between cannabis use and reproductive health outcomes," the researchers, from the U.S. National Institutes of Health (NIH), wrote in their study, published Monday (Jan. 11) in the journal Human Reproduction.

Related: How to get pregnant: 10 tips for women

However, the authors note that only a relatively small number of women in the study used marijuana, which limits the robustness of the study findings. And they did not assess marijuana use in women's partners, which could also affect conception chances. The study does not prove that using marijuana directly causes fertility problems — only that there's a link between use of the drug and lower odds of conception.  

In addition, the study involved a sample of women who had experienced a previous miscarriage, and so it is unclear if the findings would apply to the general population.

Still, until more research is available, the authors say that women should be cautious about marijuana use while trying to conceive, according to a statement from the NIH.

Marijuana and fertility 

The American College of Obstetricians and Gynecologists already recommends that women who are pregnant or trying to become pregnant  discontinue marijuana use, given concerns about the effect of the drug on the fetus' brain development. 

However, few studies have examined the effects of marijuana use on fertility. Of the small number of studies that have been conducted, all relied entirely on self-reports, which may underestimate marijuana use given the stigma of substance use.

The study researchers analyzed information from more than 1,200 women ages 18 to 40 who were trying to conceive and had experienced one or two prior miscarriages. These women, who were from four states (Pennsylvania, New York, Utah and Colorado) were originally part of a separate study looking at the effect of low-dose aspirin on pregnancy outcomes from 2006 to 2012.

The women were followed for six months while they were trying to conceive. At the start of the study, women reported if they had used marijuana, pot or hashish in the past 12 months. They also provided at least two urine samples — one at the start of the study, and another six months later if they hadn't conceived, or at the time of pregnancy if they did conceive. 

Overall, 62 women (5% of participants) either reported marijuana use in the past 12 months or had a positive urine test. (A total of 44 women self-reported marijuana use, and 33 had a positive urine test, meaning that 18 women who didn't admit to using marijuana had indeed used the drug.)

By the end of the six-month study, 42% of marijuana users had become pregnant, compared with 66% of non-users, the researchers found. And marijuana users were 41% less likely to conceive each cycle, compared with non-users. The findings held even after the researchers took into account factors that could affect fertility, such as age and body mass index (BMI) as well as alcohol use.

Studies in animals have found that marijuana may affect the lining of the uterus and make it less likely for an embryo to successfully implant, the authors said. They call for further research exploring the effects of marijuana on fertility, particularly given the increasing legalization of the drug.

Originally published on Live Science.  

Throughout history, women have been fighters, strategists and charismatic leaders, performing feats of strength, cunning and bravery. And in 2020, archaeologists uncovered intriguing evidence from the past showing that women didn't hesitate to kick butt and take names. From hoisting a spear to hurling a vengeful spell, here are six times that women from antiquity showed us that they were not to be trifled with.

Inspiration for 'Mulan'

Two women — one about 50 years old and the other about 20 — who were buried in Mongolia during the Xianbei period (A.D. 147 to 552) possibly inspired the famed "Ballad of Mulan," about a girl who served in the military in her father's place. Though the Ballad of Mulan was first transcribed by Chinese writers, tales of her brave deeds may have originated in what is now Mongolia; she is described in the ballad as serving the "khan," a term reserved for Mongolian leaders, and China did not have military conscription at the time, the researchers said. The Mongolian women's skeletal remains revealed that they were expert archers and horseback riders, and they likely fought alongside men.

Read more: Two 'warrior women' from ancient Mongolia may have helped inspire the Ballad of Mulan

Big game hunter

A 9,000-year-old burial of a female hunter sparked an investigation upending the long-held notion that men were the primary hunters in ancient hunter-gather societies, while women were relegated to collecting herbs and plants. When researchers excavated the grave in the Andes Mountains in southern Peru, they found a hunting "toolkit" near the skeleton containing multiple projectile weapons, hinting that the person was a skilled hunter and respected as such by their community. Though the remains were initially thought to belong to a man, further analysis of the bones and teeth revealed that the hunter was female. 

"These findings sort of underscore the idea that the gender roles that we take for granted in society today — or that many take for granted — may not be as natural as some may have thought," said lead author Randy Haas, an assistant professor of anthropology at the University of California, Davis.

Read more: Ancient burial of fierce female hunter (and her weapons) discovered in Peru

Road warrior

A paved 1,000-year-old limestone road connecting two ancient Mayan cities may have been built by a ruthless queen named Lady K'awiil Ajaw, so that she could expand her regional power. She ruled in Cobá in what is now Mexico's Yucatán Peninsula, and archaeologists recently reported that the Mayan queen constructed the road in order to invade a town about 60 miles (100 kilometers) to the west, called Yaxuná, which had been steadily growing in strength and threatened her rule. 

Using lidar (light detection and ranging), a remote-sensing method using laser pulses to measure distances, the researchers analyzed the ancient "white road." Earlier surveys declared that the road ran in a straight line between Cobá and Yaxuná. But the new analysis revealed unexpected twists and turns in the so-called white road that likely encompassed small settlements, which the queen's forces would also have conquered on her path to victory.

Read more: Maya warrior queen may have built the longest 'white road' in the Yucatán

Polo champ

The burial of a noblewoman named Cui Shi from ancient China included donkeys, perhaps so that she could play polo in the afterlife. Because Cui Shi was wealthy and a member of the elite, the donkeys in her tomb likely served a more important purpose in her household than merely a means of carrying heavy loads. 

Archaeologists discovered Cui Shi's tomb in 2012, and recent analysis of the donkeys' leg bones confirmed that they had a different gait than pack animals did, hinting that they were bred for quick maneuvering during high-speed polo games. Records from this period during the Tang Dynasty (A.D. 618 to 907) show that polo was popular among imperial China's upper classes, despite the game's dangers; one historic account notes that Cui Shi's husband lost an eye during a polo match.  

Read more: First proof of donkey polo in ancient China found in noblewoman's tomb

Under her spell

About 1,800 years ago in ancient Egypt, a lovestruck woman named Taromeway commissioned an "erotic binding spell" to drive a man named Kephalas mad with lust — the spell was documented in a papyrus scroll, which researchers recently translated. It called upon a ghost to hound Kephalas until he gave in to Taromeway, with "his male organs pursuing her female organs," according to the spell. The scroll also contained a drawing of Kephalas in the nude, with the Egyptian jackal-headed god Anubis firing an arrow at the naked man (presumably to inflame Kephalas' desire for Taromeway). Scholars have translated binding spells like this one before, but such spells are typically used by men to attract women, the scientists reported.  

Read more: Woman seeks man in ancient Egyptian 'erotic binding spell'

Daggers, knives and an axe

A 2,500-year-old burial in Siberia holds a woman warrior and her weapons stash, including an axe, knives and bronze daggers. There are four bodies in total in the grave — the woman, a man, an older woman and an infant — and they belonged to the ancient Tagar culture, a subset of southern Siberia's nomadic Scythian civilization. The woman was likely in her 30s or 40s when she died, and she was arranged on her back with her set of weapons positioned close by. Tagarian women were often buried with long-range weapons, so the presence of a melee-style long-handled battle axe is very unusual, one of the archaeologists said.

Read more: Ancient Siberian grave holds 'warrior woman' and huge weapons stash

Originally published on Live Science.

Why is there a persistent wage gap between men and women? Turns out, religion may play a big role in the disparity. 

New research finds that the wage gap is 8 percentage points wider in the five most religious states than in the five most secular, with women making 18% less than men in the least religious states and 26% less in the most religious. What's more, the gender gap is projected to vanish in 28 years in the most secular states, compared with a stunning 109 years in the most religious. 

"If they're in a religious community, our children are not going to know a world in which they're paid equitably," said Traci Sitzmann, an associate professor of management at the University of Colorado, Denver. "It's a little bit scary." 

Related: 20 amazing women in science and math

Religion and wages

Sitzmann and her colleague Elizabeth Campbell, an assistant professor of work and organizations at the University of Minnesota, were interested in exploring the impacts of religiosity on workforce issues. They started with a global view. Using data from 140 countries, they compared the likelihood of citizens answering "yes" to the question, "Is religion important in your daily life?" with the gender wage gap in those countries as of 2013, the most recent global data available. They found a striking association: The more religious a country, the greater the wage gap. In nations where more than 95% or more people said religion was important in their daily lives, such as Pakistan and the Philippines, women earned around 46% as much as men. 

In countries where fewer than 20% of people said religion was important to them in daily life, such as Sweden and Estonia, women averaged around 75% of men's wages. The United States had moderately high religiosity and women in the U.S. earned 66 cents for every dollar men earned, Sitzmann told Live Science. 

The effect held true for all major world religions, Sitzmann said. It didn't matter if most believers in a country were Jewish, Christian, Muslim, Buddhist, Hindu or adherants to a folk religion. The wage gap was still greater in countries where religion played a major role in daily life. 

Related: 7 sexist ideas that once plagued science

The researchers then turned to Gallup survey data on religious service attendance and the importance of religion in daily life in the 50 U.S. states. In the U.S. data, the researchers looked only at full-time wages so as not to skew the results due to women working fewer hours.

They again found that the more religious the state, the greater the wage gap. (Mississippi, Alabama, Utah, South Dakota and South Carolina were the most religious states; Vermont, Maine, Massachusetts, Rhode Island and Nevada were the least.) The researchers found that religiosity explained 17% of the variability in the gender wage gap between states. To ensure that the wider economy or levels of conservatism weren’t responsible for the difference, the researchers then looked at year-over-year data between 2008 and 2018 and found that the association between religion and wages still held. The gender gap is shrinking over time in the U.S., they found, but it is shrinking faster in secular states compared with religious ones. At current rates, it will take more than a century for the gap to close in the most religious states.

According to the workplace data analysis company PayScale, women make 81 cents for every dollar men make as of 2020. This analysis compares median salaries for men and women, and does not control for factors like seniority, years experience and education, all of which can be impacted by gender discrimination and gender role expectations.

The pathway to a wage gap

Sitzmann and Campbell found three reasons for this difference in wages between secular and religious regions. The more religious a country or state, the more that society differentiated the roles of men and women. In other words, women in more religious societies are expected to put family first. The researchers measured this by looking at how many babies women have, how many women work at all, access to abortion and family-friendly work policies. In more religious societies, women have more children, participate less in the workforce, have less access both to abortion and to policies that help balance work with family. 

Religious societies are also more likely to sexually objectify women, the researchers found. They measured this by looking at regional Google Trends for the search terms "pornography" and "rape." Both were correlated with religiosity, and both were correlated with the gender wage gap. 

Related: 7 sexist ideas that once plagued science

Finally, religious societies are also less likely to promote or accept women in leadership positions. "We've got the Pope saying, 'the door is closed, women are not allowed to be leaders in the church,'" Sitzmann said, referring to Pope Francis' 2013 statement on female priests in the Catholic Church. "That sets the stage for a very strong norm." 

She and Campbell found that in more religious societies, women have less representation in politics and in organizational leadership. They also have lower educational attainment and less legal equality. 

Closing the gap

Finally, the researchers conducted experiments to confirm that it was indeed religion, and not some closely related concept like conservatism, that explained the results. They set up an online game in which 91 participants, about half women and half men, acted as managers who had to allocate wages to employees based on performance reviews. All of the participants saw the same performance reviews, but in some cases the employee was named Patricia Anderson and in others was called Michael Taylor. 

Before seeing the performance reviews, some participants saw a description of the mock company they were working for that described it as faith-based. Others saw a description that focused on the company's dedication to communication and community. 

Those who were primed to believe they were working for a religious company allocated 3% more to the male employee compared with the female employee. In contrast, those who thought the organization was secular allocated 6% more to the female employee.

But there was a way to reverse the inequality. When the researchers told people in the mock religious company that one of the company values was that women needed to be involved, and that the company had a strict anti-sexual-harassment policy, it wiped out the gender wage gap, according to their research paper published Oct. 27 in the Academy of Management Journal.

This was a heartening result, Sitzmann said, because it suggests that simply being aware of expectations for gender equality will help make people behave more equitably. 

The major world religions all developed after humans had settled into agricultural societies in which men and women were typically prescribed different roles, said Stephanie Coontz, a historian at The Evergreen State College in Washington and the director of research and public education for the Council on Contemporary Families. Their edicts thus "tend to support a division of labor and a division of authority that put women as second-class," said Coontz, who was not involved in the new research. 

But there is a lot of room for interpretation in the major world religions' texts, Coontz added, and many passages affirm a more modern view of equality. 

"It's certainly not determinative," she said. "Many, many people who are religious have taken some of these things with a grain of salt."

National policy could help enshrine equality as a societal value, Sitzmann said. Two years ago, Iceland instituted a policy that requires companies to make their wage data available for independent review. Any company not paying men and women the same wages for equal work is fined. (The policy is currently being implemented in stages over four years, starting with the largest companies.) 

"In the end," Sitzmann said, "you want your wages to be correlated with your performance, not your gender." 

Originally published on Live Science.

Younger women may be more likely to die in the decade following a heart attack than men of the same age, a new study suggests. 

In general, women under age 50 experience fewer heart attacks than men in the same age range. The new study, published Oct. 13 in the European Heart Journal, also reflects this trend; of 2,100 heart attack patients treated at the Brigham and Women's Hospital and Massachusetts General Hospital in Boston between 2000 and 2016, only about 400 were women. The average age of all the patients in the study was 44 years old. 

But over the long-term, these young women were more likely to die than young men. The study authors followed the patients for a median of 11 years, and found that women were 1.6 times more likely to die from any cause than men during that time. 

Related: 9 new ways to keep your heart healthy 

"Notably, the differences in mortality in our study were primarily driven by non-cardiovascular death," meaning deaths not caused by a heart condition, study author Dr. Ersilia DeFilippis, a cardiology fellow at New York Presbyterian-Columbia University Irving Medical Center, told Live Science in an email. Examples of these non-cardiovascular causes of death included cancer and sepsis, a kind of overblown immune response to an infection. 

Unfortunately, "there were no clear explanations as to why women had lower survival," DeFilippis noted, though the study revealed a number of factors that may be at play.

"The risk factors for disease of other organs overlap with risk factors for heart disease," Dr. Marysia Tweet, an assistant professor in Cardiovascular Medicine at the Mayo Clinic, who was not involved in the study, told Live Science in an email. "A heart attack and the ramifications of a heart attack may affect the health of other organs. Long-term mortality is likely due to a combination of multiple factors."

Related: Why Are More Young People Having Heart Attacks?

For instance, women in the study had higher rates of diabetes than the men, as well as higher rates of diseases such rheumatoid arthritis , where joint pain and inflammation are often triggered by an immune system attack. This persistent inflammation may drive the formation of fatty plaques in blood vessels, which can block arteries and lead to a heart attack, according to a 2012 report in the journal Arteriosclerosis, Thrombosis, and Vascular Biology. That same inflammation may also affect how patients recover.

In addition, the women showed higher rates of depression than men in the study. "Depression impacts adherence to healthy lifestyle recommendations and medications," which could impact women's long-term survival after a heart attack, Tweet wrote in a commentary also published in the European Heart Journal about the research. But it's also possible that the physiological changes that coincide with depression independently worsen outcomes; for instance, elevated levels of stress hormones and inflammatory molecules called cytokines could worsen a patient's prognosis, she wrote.

In general, women are about twice as likely as men to experience stress-induced reduction in blood flow to organs after a heart attack, according to a 2018 report published in the journal Circulation. 

Related: Beyond vegetables and exercise: 5 surprising ways to be heart healthy 

Beyond these risk factors, women also received different care from men when being treated for their heart attacks. 

Women in the study were less likely than men to undergo coronary angiography, an exam in which dye is injected into the blood vessels so doctors can view those vessels and possible blockages on X-ray. They were also less likely to receive coronary revascularization, in which blood flow is restored through surgery or placement of a stent into the obstructed artery. When discharged from the hospital, women were less likely to be given medications like aspirin, beta-blockers, ACE inhibitors and statins, which are often prescribed after a heart attack to protect the organ from further damage.

These differences in medical care may reflect "persistent sex or gender disparities in clinical care and decision-making," or they may reflect clinical differences in how the men and women's heart attacks unfolded, Tweet wrote. For example, more women than men developed a spontaneous tear in an artery in the heart, which would deter doctors from performing an invasive procedure like coronary revascularization. 

Women were also less likely to have severe blockages in their coronary arteries as compared with men, which would also reduce the need for coronary revascularization, Dr. Ron Blankstein, a professor of medicine at Harvard Medical School and a preventive cardiologist at Brigham and Women's Hospital, wrote in a statement. 

Related: 7 foods your heart will hate

Socioeconomic status may be another critical factor in women's long-term survival rates, the authors wrote. "In our study, we found that women had lower median incomes than men and were more likely to have public insurance," DeFilippis said. "Therefore, there are likely differences in access to care which are playing a role."

Further studies will be needed to tease out how these factors affect women's long-term survival after a heart attack, the authors noted. In the meantime, cardiologists "need to educate women regarding the risks of cardiovascular disease and potential worrisome symptoms," DeFilippis said. In the study, chest pain was the most commonly reported symptom among both men and women, but a higher proportion of women reported symptoms like shortness of breath, heart palpitations and fatigue.

Doctors can improve women's care by recruiting more women into clinical trials, actively including sex-based data in studies of heart attacks and better addressing sex-specific risk factors when educating patients, Tweet wrote in her commentary. For instance, gestational diabetes and preeclampsia — severely high blood pressure during pregnancy — can place women at higher risk for heart attacks, she wrote. Ovary removal has also been associated with a higher risk of heart attacks, potentially because ovaries produce the sex hormone estrogen, which is thought to protect against heart disease, according to Harvard Health. 

Furthermore, some research suggests that women face greater cardiovascular risks from smoking than men do; all these risk factors warrant further study, especially in terms of whether the risk they present outmatches the protective power of estrogen and leaves women more prone to heart attacks, the authors wrote.  

Originally published on Live Science. 

Fathers forced to work from home by the coronavirus pandemic take on more childcare than their usual, new research finds. But moms are more often stuck juggling kids and work at the same time. Moms are also more stressed than men about new work-at-home arrangements. 

The closure of schools and many childcare centers has put working parents in a bind, according to the new briefing, which was written by Yale sociologists Thomas Lyttelton and Emma Zang and Kelly Musick, the chair of policy analysis and management at Cornell University, for the Council on Contemporary Families (CCF), a nonprofit research organization. In April and May of 2020, 55% of employed parents were working from home, the researchers wrote. During this time, most public schools were closed. 

Lyttelton and Zang used data from the American Time Use Survey (ATUS) collected between 2003 and 2018 to measure how telecommuting affected the division of labor pre-pandemic. This survey is run by the U.S. Bureau of Labor Statistics and asks participants to log their daily time spent doing activities such as paid work, house work and childcare. Unfortunately, the call center that runs the ATUS surveys shut down due to COVID-19 between March 19 and May 11, meaning that data from those dates were missing. To measure at least some changes during the pandemic, the researchers turned to the COVID Impact Survey, run by the Data Foundation, a nonprofit think tank that seeks to use data to improve policy, which gathered data on time use in April and May.

Related: Coronavirus outbreak: Live updates

The effects of telecommuting 

The pre-pandemic data showed that a parent who telecommutes typically takes on more of the domestic load. Telecommuting dads, in particular, take on extra childcare on work-from-home days: 67 more minutes than non-work-from-home days, to be exact. This increase actually closed the normally-seen gender gap in which women spend more time on childcare than men. When women telecommuted pre-pandemic, they added 47 minutes of childcare to their day, compared to the days when they worked away from home. 

But dads don't do any extra housework when they telecommute, while telecommuting moms take on 49 more minutes of housework. Pre-pandemic, telecommuting dads also seemed to maintain better boundaries between work and childcare while working at home. Men reported that children were with them for an average of 21 minutes a day while they worked from home, whereas women reported that they were working with their children present for 54 minutes a day. 

Many women feel pressure to keep up housework and attend to their children every time the kids interrupt, said Stephanie Coontz, a sociologist at The Evergreen State University in Washington and the director of research at CCF. "This is a form of work-family conflict people often ignore when they tout the advantages of working from home, and as this report shows, it's a source of gender inequality at home and at work."

Related: Doting dads: 6 of history's finest fathers

Pandemic work-from-home

Given the shutdown of ATUS data collection, the researchers couldn’t directly compare these pre-pandemic results to the situation during the pandemic. The COVID-19 Impact Survey did show, however, that all parents who worked from home during the pandemic were more depressed than those still reporting to a workplace. Mothers were hit particularly hard. Moms telecommuting during the pandemic reported more anxiety, loneliness and depression than telecommuting dads. Moms who did their work outside the home reported no such increase, and telecommuting dads actually felt less anxiety than dads who were reporting to a workplace.

Notably, the data showed that the worst position to be in was to be unemployed: Unemployed mothers and fathers were consistently more anxious, depressed, lonely and hopeless than parents who still had jobs. 

In May, a  previous CCF survey of 1,060 parents in different-sex couples found that both men and women agreed that men were carrying more of the domestic load during the COVID-19 pandemic compared with what they did pre-pandemic. Pre-pandemic, 26% of couples reported sharing housework relatively equally, a number that rose to 41% in April. Forty-one percent of couples pre-pandemic reported sharing the care of young children equally, which rose to 52% after the pandemic began. That survey also found that stay-at-home orders had lessened some of the domestic load by eliminating tasks like hauling children to extracurricular activities or planning their daily schedules. 

However, the picture gets murkier when zooming in specifically on homeschooling children. An April survey commissioned by The New York Times found that 80% of women said they were doing most of the schooling of their children, compared to 45% of men. Clearly, given that these numbers add up to more than 100%, a significant number of couples disagree about who is doing the most. Only 3% of women agreed that their male partners were doing the most when it came to teaching kids at home. 

Editor's note: This article was updated to correct the spelling of Emma Zang's name.

Originally published on Live Science.

A small new study found signs of damage to the placenta in pregnant women with COVID-19, but it's far too early to say whether this damage actually affects birth outcomes. Most women with the novel coronavirus who had these abnormalities gave birth to healthy babies at-term. 

The study researchers examined placentas from 16 pregnant women who tested positive for COVID-19, and found that the placentas contained blood clots and showed signs of abnormal blood flow between mother and baby. 

However, the study does not prove that COVID-19 was behind these abnormalities with the placenta. Indeed, nearly half of pregnant women without COVID-19 who had their placentas examined for other reasons also show such signs of injury. 

In addition, given that most of these women had normal pregnancies and delivered seemingly healthy babies at full-term, it's unclear these placental changes mean much. The researchers note that even partly damaged placentas can often supply babies with sufficient nutrients. 

"Placentas get built with an enormous amount of redundancy," study co-author Dr. Emily Miller, an assistant professor of obstetrics and gynecology at Northwestern University Feinberg School of Medicine in Chicago, said in a statement. "Even with only half of it working, babies are often completely fine."

Still, Miller added "there's a risk that some pregnancies could be compromised." The findings suggest the need to closely monitor pregnant women with COVID-19, the authors concluded.

Such monitoring might include ultrasounds to measure if the baby is growing at a typical rate, and so called non-stress tests that check how well the placenta is delivering oxygen, the researchers said.

However, experts not involved with the study expressed concern that many other diseases in pregnancy could lead to similar injury to the placenta, and so it's too soon to know if these changes were caused by COVID-19.

Related: 5 Reasons Why Placentas Are Amazing 

Signs of injury 

The placenta is a vital structure that supplies oxygen and nutrients to the baby in utero, and removes waste products from the baby's blood, according to The Mayo Clinic. Some viral infections in pregnancy, such as cytomegalovirus and Zika virus, are known to be linked with abnormalities in the placenta, but whether this occurs with coronaviruses is unknown. (These diseases can also lead to problems after birth, such as the microcephaly, or reduced head volume, caused by Zika virus.)

The new study, published May 22 in American Journal of Clinical Pathology, is one of the largest to examine placentas in pregnant women with COVID-19. Among the 16 women in the study, 15 delivered in the third trimester, and one experienced a miscarriage in the second trimester. The researchers don't know whether the miscarriage was related to the woman's COVID-19 infection.

The researchers compared the placentas of these 16 pregnant women with COVID-19 with those of 17,479 women without COVID-19 who required a placental examination, often because they had pregnancy-related conditions, such as preterm birth or preeclampsia. But within this group of "controls" were 125 women who had melanoma. The authors chose to focus on this group in particular because they require placental examination after birth to check for cancer spread; but melanoma itself is not thought to affect pregnancy outcomes.

About 80% of the women with COVID-19 showed a type of placental injury known as "maternal vascular malperfusion," which is a sign of insufficient blood flow between mother and baby due to abnormal blood vessels. In contrast, 27% of women with melanoma and 44% of all controls (women without COVID-19 with and without melanoma) showed this abnormality.

"Our findings indicate a lot of the blood flow was blocked off, and many of the placentas were smaller than they should have been," Miller said.

In women with COVID-19, the researchers also observed "intervillous thrombi," or blood clots in the placenta. This finding fits with research showing that some patients with COVID-19 experience clotting problems, the authors said.

Skepticism 

However, Dr. Kristina Adams Waldorf, a professor of obstetrics and gynecology at the University of Washington School of Medicine, did not find the results convincing. 

"I'm concerned that the scientists that wrote this manuscript have taken a leap from seeing some placental pathology to the conclusion that the virus does in fact cause injury," Adams Waldorf told Live Science. She noted that there are "many many other conditions that can cause a similar profile of placental pathology." This makes it hard to tease out the effects of COVID-19 from other common conditions during pregnancy, such as high blood pressure, obesity and diabetes, she said.

Much larger studies that take into account these common pregnancy conditions are needed to get a better picture of the specific effects of COVID-19 in pregnancy, she said. 

Other studies in lab dishes can look at the effects of the virus on placental cells. Adams Waldorf is currently conducting lab studies to examine the placenta's antiviral immune response to the virus.

In addition, most of the women in the current study contracted COVID-19 late in pregnancy, in the third trimester, but little is known about the effects of the virus early in pregnancy.

The new study also found that, among the 15 live births to women with COVID-19, none of the babies tested positive for the disease. 

One recent study suggested that three babies in China may have contracted the new coronavirus in the womb, in what's known as vertical transmission, but these findings were inconclusive, Live Science previously reported. Overall, evidence so far suggests that vertical transmission is "at most, very rare," the authors of the new study wrote.

•  Are you pregnant? 12 early signs of pregnancy 
•  18 ways pregnancy may change your body forever 
•  20 of the worst epidemics and pandemics in history 

Originally published on Live Science.  

More men than women have fallen severely ill or died from COVID-19, and now two clinical trials will probe whether sex hormone differences might explain the trend, The New York Times reported.

Since the COVID-19 pandemic first emerged in China, men around the world have been more likely to require intensive medical care or die from the disease than women, according to the Times report. For instance, men make up about 75% of the COVID-19 patients in intensive care or on ventilators at Cedars-Sinai Medical Center in Los Angeles, Dr. Sara Ghandehari, a pulmonologist and intensive care physician, told the Times. And as of early April, infected men in New York City were dying at about twice the rate of infected women, according to NPR. 

The trend may be related to the high prevalence of heart and lung conditions in men, who also generally smoke cigarettes, consume alcohol and are exposed to outdoor air pollution at higher rates than women, Sarah Hawkes, professor of global public health at University College London, told NPR on an episode of Morning Edition. In addition to these factors, though, "there's quite a lot of good evidence that ... female immune systems are essentially a lot stronger," she added. 

Related: 10 deadly diseases that hopped across species

The sex hormones estrogen and progesterone, which women produce in larger quantities than men, help to regulate the female immune system and may grant women special resistance against infections and harmful immune system responses, the Times reported. With that in mind, scientists at Cedars-Sinai and the Renaissance School of Medicine at Stony Brook University plan to treat small groups of COVID-19 patients with the hormones, to see if they make a difference. 

"We may not understand exactly how estrogen works [to counteract COVID-19], but maybe we can see how the patient does," Dr. Sharon Nachman, the principal investigator of the Stony Brook University trial, told the Times. 

The Stony Brook trial will include 110 patients with confirmed or presumed cases of COVID-19 who develop at least one serious symptom, such as high fever, shortness of breath or pneumonia, but do not yet require mechanical breathing support through intubation, according to ClinicalTrials.gov. All men ages 18 and older may enter the trial, as well as women ages 55 and older (women's estrogen levels tend to decline after menopause.) Half the participants will be treated with an estrogen patch placed on their skin for one week, while the other half will receive standard medical care. 

Previous research suggests that extra estrogen could help clear the virus from the body, as well as support repair of damaged tissues once the COVID-19 infection begins to subside, Nachman said.

Participants in the Cedars-Sinai trial will receive progesterone, rather than estrogen, as progesterone may have anti-inflammatory properties and could prevent the onset of a so-called cytokine storm, wherein inflammatory chemical signals go haywire and damage the body, Ghandehari told the Times. The study will include 40 hospitalized men with mild to moderate COVID-19 infections. Half of those men will receive two shots of progesterone a day for five days. Both the estrogen and progesterone trials will monitor the severity of patients' illnesses through time, comparing the treated groups with the untreated groups.

Both trials bank on the idea that heightened levels of estrogen and progesterone may help the body fight COVID-19 infection, but not all the data supports that notion, Sabra Klein, who studies sex differences in viral infections and vaccination responses at the Johns Hopkins Bloomberg School of Public Health, told the Times.

"Older men are still disproportionately affected" by COVID-19 compared with older women, whose hormone levels dip dramatically following menopause, she said. "That suggests to me it's got to be something genetic, or something else, that's not just hormonal," she said. That said, infusions of estrogen and progesterone may still modulate the male immune system in a beneficial way, Klein added.

"You could get a beneficial effect in both men and women," she said. "But if women are better at recovery at 93 years old, I doubt it's hormones."

•  Going viral: 6 new findings about viruses 
•  The 12 deadliest viruses on Earth 
•  Top 10 mysterious diseases 

Originally published on Live Science. 

The reason for the female orgasm has long eluded scientists. Men need them for reproduction; women don't. So why do female orgasms exist?

Scientists studying this issue are divided, said David Puts, a biological anthropologist at Penn State University. Some scientists think female orgasms are totally purposeless. But evidence suggests that they may have once helped (and perhaps still help) us survive and reproduce.

One theory holds that women have orgasms because men have them, said Kimberly Russell, an ecologist at Rutgers University in New Jersey. Some researchers argue that female orgasms exist because as fetuses, we all start out with the same basic parts, regardless of sex. Orgasms in women, like nipples on men, just happen to stick around.

Related: What's an orgasm?

"It might be an anatomical bonus," she told Live Science. In this scenario, the orgasm didn't evolve specifically for females, and it might not serve a specific evolutionary function for them. 

But there's a problem with the argument that orgasms have no function, said Patricia Brennan, an evolutionary biologist at Mount Holyoke College in Massachusetts. It's not adaptive for our bodies to devote too much energy to traits, like nipples, that aren't beneficial. These traits tend to disappear or become less pronounced over time. That's far from the case for female orgasms, she said. According to the Kinsey Institute, female orgasms tend to last longer than male orgasms and can occur multiple times in a row — something that's rare in men. In other words, female orgasms use a lot of energy for a trait that supposedly has no function, she said.

Plus, there's nothing diminished about the anatomical structures involved in the female orgasm, Brennan noted.

The clitoris, a highly sensitive part of the female genitals that has a key role in orgasms, is homologous to the penis. Like male and female nipples, they grow from the same anatomical structure. But contrary to popular belief, Brennan told Live Science, "a clitoris is not just a mini penis."

The human clitoris has “structures that are incredibly well developed,” Brennan said. "To me, that screams selection."

There are multiple theories about how, exactly, the female orgasm helped our ancestors pass on their genes. Although women don't need to have an orgasm to conceive, some research suggests that wasn't always the case. Many female mammals, including rabbits and cats, ovulate only when they mate. Based on an analysis of how traits have been passed down through the tree of life, one study published in the Journal of Experimental Zoology found that our female ancestors probably needed orgasms in order to reproduce.

But again, this theory doesn't explain why orgasms stuck around in women, Brennan said. 

"If orgasms evolved for some adaptive reason, but they're no longer adaptive, they should have disappeared. And clearly they haven't gone away," Brennan said.

Some research suggests that orgasms still create the perfect conditions for conception — even if they're not necessary to ovulate. One study found that women who had orgasms close to when their male partner did actually "upsucked" more sperm into their bodies compared with women who had orgasms much earlier or later than their partner. Scientists have even tried to draw correlations between the number of orgasms a woman has and the number of children she has. But the evidence for these hypotheses is shaky and doesn't draw a direct causal link between orgasms and conception, Puts told Live Science. 

Plus, these theories leave a major question unanswered, Russell said. What if the orgasm has nothing to do with reproduction? What if, instead, it evolved only for pleasure?

Sex doesn't have to feel good for reproduction to take place, Russell said. "We know this from looking at animals! Sex can be very uncomfortable and still gets done," she said. But culturally, the idea that sex might be for more than just babies is somewhat of a taboo topic, Russell said.

Sex that feels good for both males and females has an important social role, Russell said. It relieves stress and helps partners bond. Ancestral humans might have engaged in sex to create more cohesive groups, smoothing over conflict and cementing their social network. We see these behaviors in other primates, like bonobos, who might use sex to help dispel a fight over a tasty piece of fruit or even a clan rivalry, the BBC reports. It follows from this argument that evolutionarily, female orgasms might have acted as a kind of social glue. 

That pleasure alone is enough to make a trait adaptive goes against popular conceptions of why sex, and orgasms, exist. But for Brennan, it makes perfect sense. "To experience pleasure — that seems evolutionarily like a good idea," she said. 

• Why do guys get sleepy after sex?
• What is the 'birds and the bees'?
• Why do we have sex? 

Originally published on Live Science.

A new prize was just founded to honor the late Maryam Mirzakhani, a brilliant Iranian mathematician who died of breast cancer in 2017. The $50,000 prize will go to outstanding young female mathematicians who are no more than two years out from earning their doctoral degrees.

"We hope that the Maryam Mirzakhani New Frontiers Prize will help inspire young women to pursue their calling for mathematics," said Richard Taylor, the chair of the selection committee for the Breakthrough Prize in Mathematics, which is awarding the money. "Recognizing some of the many aspiring women in mathematics is a fitting tribute to the beautiful intellect of Dr. Mirzakhani."

Mirzakhani was just 40 when she died, only three years after winning one of math's most prestigious prizes, the Fields Medal. Mirzakhani was the only woman to have ever won the prize, which is handed out to mathematicians under age 40. Mirzakhani's close collaborator, mathematician Alex Eskin of the University of Chicago, won a $3 million Breakthrough Prize this year for work he did in conjunction with Mirzakhani. The pair had worked out a theorem to explain some of the features of a geometric concept called moduli space. Mirzakhani was also well known for her work in understanding the geometry of spheres, doughnuts and other curved, three-dimensional shapes, according to Stanford University, where she was a professor. 

Mirzakhani was born in Tehran and in high school became the first female ever to compete on Iran's International Mathematical Olympiad team, according to her Stanford University obituary. She won gold medals in that competition in 1994 and 1995. She attended Harvard University for graduate school and solved two long-standing mathematical problems in her doctoral thesis. 

The $50,000 prize money may be split between two or more individual mathematicians. Details on eligibility for the Maryam Mirzakhani New Frontiers Prize will be available on the Breakthrough Prize website.

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Originally published on Live Science.

Science is supposed to be objective — right? By following a careful set of steps, it can tell us how the world works. But looking back on history, that's not at all true, experts say. In reality, science was used again and again to reaffirm whatever prejudices were in vogue at the time — including the idea that women are weaker, crazier, less smart and generally less capable than men. 

Here are seven hysterical ideas about women that were once scientific dogma.

Those pesky wombs cause all sorts of problems 

Feeling a little off? If you have a womb, you might want to make sure it hasn't wandered out of place, according to ancient Greek and Egyptian doctors. Hysteria, a condition described in the oldest medical document ever recovered, was attributed only to women. Its symptoms were mainly psychiatric and ranged from depression to a "sense of suffocation and imminent death," according to an article published in 2012 in the journal Clinical Practice and Epidemiology in Mental Health. 

Hysteria happened, scientists from the second century B.C. believed, when a womb just would not stay put. (The word "hysteria" even comes from the Greek word for womb, "hustera") Depending on whom you consulted, cures ranged from sexual abstinence to prescribed sex. Or perhaps, some argued, an herbal mixture would be sufficient to fix the problem.

By the 19th century, physicians no longer believed that the womb wandered. But many of the ideas underlying the concept of hysteria — for instance, that female reproductive organs could be blamed for psychiatric problems — stuck around. In fact, as late as 1900, many asylums still performed routine gynecological examinations on their patients , according to a 2006 article written by University of Manchester historian Julie-Marie Strange and published in the journal Women's History Review.

A vibrator could solve all our problems

By the early 20th century, when Sigmund Freud was revolutionizing the field of psychiatry, men and women both received treatment for hysteria. Even then, some doctors still attributed the condition to sexual or reproductive dysfunction in women. Some doctors would use streams of water to induce "hysterical paroxysm" (otherwise known as an orgasm) in women. In the 1880s, Dr. Joseph Mortimer Granville invented a medical tool especially for inducing these paroxysms and curing hysteria, Vogue reported. That tool eventually evolved into the vibrator.

Doctors should be careful not to excite women's passions "too much"

While some doctors prescribed sex to cure women of mental illness, other physicians worried that routine medical checkups might be a little too titillating. In an 1881 issue of the prestigious medical journal The Lancet, doctors said that gynecological exams could "ignite sexual passions in women" and encourage women to "satisfy their own lusts." One husband at the time even complained that the speculum had caused the downfall of his marriage, Strange wrote in Women’s History Review. 

Speaking of your womb, did you know it could fall out if you run too much?

In 1967, Kathrine Switzer became the first woman to officially sign up for the Boston Marathon — but race officials didn't know she was a woman. When she told her male training partners she was planning to run the race, they protested, Switzer wrote in her memoir. They thought it was too much for a fragile woman's body, fearing that her uterus might even fall out. 

This myth might come from a journal article published in 1898 in the German Journal of Physical Education, according to a 1990 study in the Journal of Sports History. In that 1898 study, a Berlin doctor wrote that exertion could cause the uterus to shift position in the body, resulting in sterility, "thus defeating a woman's true purpose in life." 

Today, with more women entering endurance sports, the idea that too much jiggling will cause your uterus to fall out has also fallen out of favor. But the notion still occasionally crops up. In 2005, Gian-Franco Kasper, the president of the International Ski Federation, said on NPR that ski jumping is "not appropriate for ladies from a medical point of view." In 2010, he elaborated on his point by arguing that a woman's uterus could burst when she landed, Outside magazine reported.

Women are basically small men

Until very recently, doctors and scientists considered women, medically speaking, basically the same as men. 

"For a very long time, researchers in many fields believed there was a single body and that it was not gendered at all," Naomi Rogers, a historian at Yale School of Medicine, told Live Science.

That is, men were considered the default setting and women were variations on that mold. In fact, it was only in 2000 that the medical community formally acknowledged that "women are not small men," Vera Regitz-Zagrosek wrote in the book "Sex and Gender Aspects in Clinical Medicine" (Springer 2012). This assumption has had profound implications for female patients.

For example, until 2000, women were not always included in clinical trials — meaning that many drugs had been tested only on men, with no sense of how the medications might interact with a woman's body.

But weirdly, our brains are totally different

One of science's more persistent ideas about women is that they're fundamentally different from men in behavior and intelligence due to differences in their brains. That idea began with the field of phrenology, the study of head size that reached peak popularity in the 19th century. For years, scientists argued that women's smaller heads were a sign of their inferior intelligence. 

Later, scientists realized that women actually had larger heads in proportion to their bodies. So, researchers proceeded to argue that because women's proportions are more similar to those of children (who also have proportionally larger heads), women must be intellectually similar to children, wrote Margaret Wertheim in the book "Pythagoras's Trousers: God, Physics and the Gender War" (W. W. Norton & Company, 1997). 

"You can see the incredible appeal of brain size” as a measure of intelligence, Rogers said. But, she added, phrenology has long been debunked as pseudoscience.

Unfortunately, the idea that differences in female and male brains account for fundamental differences in personality and behavior still arises, Susan Castagnetto, a philosopher at Scripps College in California, told Live Science. For example, differences in the proportion of gray matter and white matter have been used to argue that men are more "systematizing" and that women are more "empathizing." 

But, Castagnetto pointed out, there's one major problem with this field of research: We don’t know what this difference actually does. "How do you conclude anything about actual performance based on finding [anatomical] sex differences in the brain?" she said.

There may be differences between male and female brains, but we can't conclude what those differences mean, Castagnetto said.

Periods make women even less fit

Another age-old idea is that people who menstruate are less capable of performing tasks — like leading, attending school or even being good mothers. Beginning in the Victorian era, doctors referred to menstruation as an illness or a disability, Strange wrote. In an article titled "Sex in Education: or a fair chance for the girls," American Doctor Edward Clark wrote that because women menstruate, they have less blood overall compared to men, and therefore less energy. He extrapolated that because of their limited blood supply, school would downright dangerous for girls. After all, he argued, studying could divert a girl's limited blood supply away from vital organs (like her uterus and ovaries).

Though the idea of "limited blood supply" seems comical today, the notion that people who menstruate become indisposed once a month has stuck around. In 1975, Psychology Today ran an article titled "A person who menstruates is unfit to be a mother," Carol Tavris wrote in her book "The Mismeasure of Woman" (Touchstone, 1992). Today, a host of undesirable symptoms — from confusion to asthma to lowered school performance — are all chalked up to menstruation under the name premenstrual syndrome (PMS), Tavris wrote.

"Mercy!" she wrote. "With so many symptoms, accounting for most of the possible range of human experience, who wouldn't have PMS?"

Editor's Note: This story was updated to correct Susan Castagnetto's area of expertise. She is a philosopher, not an ethicist.

When archaeologists discovered the remains of a woman in a Viking graveyard in Denmark, an axe near her skeleton told them that she may have been a fighter. But closer examination of both the weapon and her burial revealed something unexpected: She was no Viking.

Rather, the woman was Slavic, and likely came from a region in Eastern Europe that is now Poland, representatives of Poland's Ministry of Science and Higher Education said in a statement.

A coin from the cemetery, on the Danish island of Langeland, revealed that the burial site is about 1,000 years old, according to the statement. The woman's grave was the only one that held a weapon. [Beyond Wonder Woman: 12 Mighty Female Warriors]

Throughout history and across the globe, women have wielded weapons. In recent years, archaeologists have found evidence that some Viking women were buried with weapons. But in many of those cases, there were no human remains in the graves, and the gender of the former occupants was inferred from the presence of jewelry and other objects that typically belonged to women, Leszek Gardeła, an archaeologist with the University of Bonn in Germany and the University of Bergen in Norway, said in the statement.

However, the Slavic woman's skeleton was still lying in the grave. The skeleton showed no obvious injuries that would have indicated how she died, Gardeła said. The axe resembled similar tools from the southern Baltic — a region that includes modern countries bordering the Baltic Sea, such as Poland, Germany and Lithuania — and the chambered construction of her grave is reminiscent of cemetery structures from that part of the world during the Middle Ages.

During this period in Denmark, Slavs and Scandinavians lived close together, which would explain why a Slavic woman was laid to rest in a Danish graveyard, Gardeła said in the statement.

To date, approximately 30 graves of women containing weapons have been discovered in Norway, Denmark and Sweden. Of those, 10 graves — including that of the Slavic warrior — were identified by Gardeła. His findings will be published in 2020 as part of a project investigating Viking and Slavic women warriors, titled "Amazons of the North," according to the statement.

• Photos: Viking Warrior Is Actually a Woman
• 5 Myths About Women's Bodies
• Photos: 10th-Century Viking Tomb Unearthed in Denmark

Originally published on Live Science.

The Food and Drug Administration (FDA) recently approved a new drug to treat low sex drive in women.

But how exactly does the drug work, and what makes it different from the other medication on the market?

The drug, called bremelanotide (brand name Vyleesi) has been approved to treat premenopausal women with hypoactive sexual desire disorder (HSDD), a condition in which low sexual desire causes personal distress, the FDA said in a statement. It is only the second FDA-approved drug for HSDD in women.

Women self-administer the injection under the skin of the abdomen or thigh at least 45 minutes before anticipated sexual activity. Women should not take more than one dose of bremelanotide within a 24-hour period or more than eight doses per month. [5 Myths About Women's Bodies]

In a study of more than 1,200 premenopausal women with HSDD, 25% of those who took bremelanotide saw some improvements in their reported sexual desire scores, compared with 17% who took a placebo.

Bremelanotide binds to receptors in the brain called melanocortin receptors, which play a role in many biological functions, such as metabolism and food intake, skin pigmentation and pain regulation. But it's unclear exactly how the drug works to boost sexual desire, the FDA said.

However, the main theory is that bremelanotide works by increasing dopamine — a brain chemical involved in reward processing — in certain parts of the brain, said Sheryl Kingsberg, chief of the Division of Behavioral Medicine at University Hospitals Cleveland Medical Center, who has studied bremelanotide. This, in turn, allows women to "process erotic stimulation as rewarding," said Kingsberg, who has received consulting payments from AMAG Pharmaceuticals, which markets Vyleesi, and Palatin Technologies, which developed the drug.

Kingsberg told Live Science that it's theorized that normal sexual function relies on a balance of excitatory and inhibitory signals in the brain, and HSDD is the result of either not enough excitation or too much inhibition. Within this line of thinking, bremelanotide is hypothesized to promote the excitation response by releasing dopamine, she said.

The only other FDA-approved drug for HSDD is flibanserin (brand name Addyi). Flibanserin acts on a different brain receptor, and it partially blocks the production of the brain chemical serotonin, Kingsberg said. Serotonin is thought to dampen sex drive in part by inhibiting the excitatory dopamine system, according to a 2017 review in The Journal of Sexual Medicine.

The two drugs also differ in their dosing frequency — flibanserin needs to be taken every day at bedtime, while bremelanotide is taken as needed. Drugs used to treat male sexual dysfunction, such as sildenafil (brand name Viagra), mainly target an enzyme called phosphodiesterase 5 (PDE5), which plays a role in regulating blood flow to the penis. By blocking the enzyme, sildenafil's overall effect is to increase blood flow to the penis, which leads to an erection. However, sildenafil does not boost sex drive.

The most common side effects of flibanserin are sleepiness and dizziness, while the most common side effect of bremelanotide is nausea, Kingsberg said.

In studies of bremelanotide, 40% of women experienced nausea, most commonly with their first injection of the drug, and 13% needed to take treatments for their nausea, the FDA said. Still, more than 90% of women who experienced nausea stayed in the drug trial, suggesting that either their nausea was mild or they felt that the benefits of the drug outweighed the side effect, Kingsberg said.

Bremelanotide shouldn't be used in people with uncontrolled high blood pressure or those with heart disease, the FDA says. In addition, patients should stop taking bremelanotide after eight weeks if they don't experience an improvement in their sexual desire and related distress.

• 51 Sultry Facts About Sex
• Can a Pill Increase a Woman's Libido? 5 Things That Affect Female Sex Drive
• Wonder Woman: 10 Interesting Facts About the Female Body

Originally published on Live Science.

Drinking alcohol is known to raise women's risk of developing breast cancer, but many women aren't aware of this link, a new study from the United Kingdom suggests.

The study researchers analyzed information from 205 women who were undergoing breast cancer screening or seeking treatment for breast cancer symptoms at a U.K. hospital. The women were surveyed about their knowledge of risk factors for breast cancer.

About half the women surveyed knew that smoking was a risk factor for breast cancer, and 30% recognized obesity as a risk factor. But only about 20% knew that consuming alcohol was a risk factor, the study found.

Even among health care staff, knowledge of the connection between alcohol and breast cancer was still lacking — of 33 health care staff surveyed, 49% identified alcohol as a risk factor for breast cancer. [7 Odd Things That Raise Your Risk of Cancer (and 1 That Doesn't)]

The new study was conducted at a single health center in the U.K., and so the findings don't necessarily apply to the general population. But the findings do agree with previous research conducted in the United States: A 2017 survey by the American Society of Clinical Oncology found that 70% of Americans didn't know that drinking alcohol is a risk factor for cancer.

It's estimated that alcohol consumption is responsible for around 5% to 11% of all breast cancer cases, with higher risks seen among heavy drinkers. A recent study also estimated that drinking a bottle of wine a week is the equivalent of smoking 10 cigarettes per week for women, in terms of their overall cancer risk.

The new study also suggests that it may be difficult for people to estimate exactly how much alcohol they consume. The study showed that more than half of participants couldn't correctly estimate the alcohol content in any of four commonly consumed alcoholic drinks — a glass of wine, a pint of beer, a liter of cider and a bottle of liquor.

"This suggests that many women may be unaware that their level of alcohol consumption may be increasing their risk of breast cancer," the authors wrote in the June 18 issue of the journal BMJ Open.

It's possible that breast cancer screenings and visits for breast cancer symptoms might serve as "teachable moments" to inform women about ways to decrease their breast cancer risk, such as by reducing alcohol consumption, the authors said.

Indeed, when women in the study were asked how they would feel about having a 5-minute session in which they were provided with cancer prevention information at their breast cancer screenings or appointments for breast symptoms, about 30% percent said this would make them more likely to attend those appointments, and 70% said it would make no difference.

This suggests that "women would not be put off attending breast [cancer] screening or clinic appointments if they were aware they would receive some cancer prevention education," and may in fact be more likely to attend, the authors said.

However, more research would be needed about how to best deliver such information. Both patients and health care providers expressed concern that such sessions might come across as placing stigma on women who drink or blaming women for drinking.

• 5 Myths About Women's Bodies
• 10 Do's and Don'ts to Reduce Your Risk of Cancer
• 7 Ways Alcohol Affects Your Health

Originally published on Live Science.

(Spoiler Alert! This article contains information about the last episode of "Game of Thrones.")

After eight seasons, the epic "Game of Thrones" TV series finally resolved the question of who will reign — with an unexpected twist. Bran "the Broken" Stark rolled into position as the new monarch of the Six Kingdoms, but no longer will a king or queen's rule be automatically inherited by their children.

And that's a good thing: Much of the political upheaval throughout the HBO series stemmed from uncertainty about the lawful heir to the throne. While it's anyone's guess what lies ahead for Westeros under its new system, we know from European history that hereditary succession can cause disruptions that reverberate to this day.

In fact, researchers recently found that when male heirs for medieval European monarchies were in short supply, the resulting social discord hampered economic growth for generations. As a result, countries in regions that lacked male heirs "are today poorer than other regions," scientists reported online March 11 in the journal Comparative Political Studies. [5 Real-Life Inspirations for 'Game of Thrones' Characters]

During the Middle Ages in Europe, around the years 1000 to 1500, direct male descendants were the most desirable heirs for a throne or noble title. Women and distant male descendants could also fill those roles; however, these were more likely to spark dissent and violence among rival groups of supporters, and the fighting could undermine future economic growth, the researchers wrote.

In regions where monarchs were lucky enough to have male heirs, allowing for uncontested leadership transitions, "rulers were able to build the state institutions necessary to support economic development," the scientists wrote.

"In areas burdened by a greater potential for political instability, the path to economic prosperity was much more arduous," the researchers said.

What about illegitimate male heirs? In "Game of Thrones," King Joffrey Baratheon called for the murder of all his father's bastards so that none could challenge the new king's claim to the throne. But in the study, the researchers determined that medieval taboos against succession by illegitimate sons were so strong that the number of bastard "heirs" didn't have much of an effect on medieval politics.

Over the centuries, other factors across Europe also shaped social and economic fortunes, the scientist reported. But the fingerprints of medieval hierarchies left a powerful imprint; France and Naples, for example, had consistent male lineages during the Middle Ages, and even today, those areas tend to be better off economically than some of their neighbors, according to the study.

"The emergence of the first modern states in this period was so important, and the states themselves so fragile, that even small disruptions could have long-term consequences," the researchers wrote.

Fans of "Game of Thrones" will have to imagine for themselves whether Westeros' new approach to leadership — where new rulers are chosen by a noble council, rather than preordained by heredity — will prove successful. Judging from the council's uproarious reaction to Sam Tarly's proposal that they empower the common people to choose a leader, the Six Kingdoms clearly isn't ready to embrace democracy just yet.

• Photos: 33 Stunning Locations Where 'Game of Thrones' Was Filmed
• Move Over, 'Game of Thrones,' Here Are 9 Real-Life 'Dragons'
• Family Ties: 8 Truly Dysfunctional Royal Families

Originally published on Live Science.

Revolutionary War hero Casimir Pulaski was a dashing young officer who served under George Washington. But a new examination of his remains reveals that he wasn't exactly the gentleman that he appeared to be.

Pulaski, an exiled Polish nobleman, founded America's first cavalry division. He died in battle in 1779 and his remains were entombed inside a monument in Savannah, Georgia, in 1854. But when the tomb was opened more than a century later, experts made a startling discovery: Some features of the skeleton were female.

At that time, scientists were unsure if the body was Pulaski's or that of an unknown woman whose remains were mistakenly placed in Pulaski's tomb. However, new DNA analysis confirms that the skeleton belongs to Pulaski, raising intriguing questions about the general's gender. [The Truth About Genderless Babies]

Details of this incredible story were recently described in "The General Was Female?," an episode in the series "America's Hidden Stories" that premiered yesterday (April 8) on the Smithsonian Channel. 

Born in Poland in 1745, Pulaski's military expertise fueled his rise to the role of Brigadier General during America's struggle for independence. He formed a legion that combined cavalry and infantry, called the Pulaski Legion; the generalis known as "The Father of the American Cavalry," according to the National Parks Service.

When the Pulaski monument in Savannah was opened in 1996, experts determined that the skeleton inside was female based on the shape of the pelvis and features in the skull, "such as a delicate midface, with the jaw at more of an obtuse angle," Virginia Estabrook, an assistant professor of anthropology at Georgia Southern University, told Live Science.

But did that mean that Pulaski was actually a woman — or was the body not Pulaski's? Experts conducted genetic tests, comparing DNA from the skeleton with DNA collected from a deceased Pulaski relative. Though the forensic team's results were inconclusive, the body was reburied in 2006 as Pulaski's, Estabrook said.

A portrait of the Revolutionary War general Count Casimir Pulaski, engraved by H.B. Hall and published in 1871. Credit: National Archives at College Park

Recently, Estabrook and other experts revisited this historic mystery, analyzing mitochondrial DNA by using a database not available in 2006. They found that DNA from Pulaski and from a maternal relative matched each other more closely than DNA of 27,000 other genetic profiles in the database. This strongly suggested that the two were related — and that the remains in the monument were Pulaski's, Estabrook said.

What's more, the skeleton also preserved known details from Pulaski's life, such as height and build; an old heel injury; and wear in the hip sockets consistent with long-term horseback riding.

Pulaski was almost certainly not a woman living secretly as a man; the general's entire life was conducted as a male identity, and he was christened Casimir — a man's name — as an infant, Estabrook said. However, the researchers proposed something that was not seriously considered when the skeleton was examined 15 years ago: the possibility that Pulaski was intersex, possessing both male and female characteristics.

Intersex is a blanket term for a number of conditions in which development patterns don't all fit neatly into exclusively male or female categories. For instance, babies that are genetically female (two X chromosomes) may have an enlarged clitoris that resembles a penis, while babies that are genetically male (one X and one Y chromosome) may have an abnormally small penis and no testicles, according to the Mayo Clinic.

For Pulaski, one possible explanation could be a condition called congenital adrenal hyperplasia (CAH), which can cause females to develop genitals that look more male than female, Estabrook said. Increased androgen production from CAH could also cause someone who was chromosomally female to have a slightly receding hairline and facial hair — as evident on Pulaski in portraits of the general.

Many cultures recognize more than two genders, and some include as many as five, according to Estabrook. Yet remains in archaeological sites are typically interpreted as either male or female, even when a body is buried with gendered objects that aren't consistent with the skeleton's biological sex. Such was the case of the so-called Viking warrior woman, who appeared to be biologically female and was buried with an array of weapons that are usually found in the graves of men.

"What we haven't really thought about is that maybe some of these individuals may have been some form of intersex as well," Estabrook said.

• Men vs. Women: Our Key Physical Differences Explained
• Why Is Pink Associated with Girls and Blue with Boys?
• Photos: Viking Warrior Is Actually a Woman

Originally published on Live Science.

When a woman gets pregnant while on the pill or other hormonal birth control, doctors often assume she didn't use the contraceptive properly. But a new study suggests that, in some cases, a woman's genes may put her at risk for an unplanned pregnancy even while using hormonal birth control properly.

The study found that, while on hormonal birth control, women with a relatively rare version of a gene called CYP3A7 tended to have lower blood levels of the hormones needed for the birth control to work, compared with women who had more common versions of the gene.

The CYP3A7 gene codes for a liver enzyme that's typically active only in fetuses and is switched off before birth, the researchers said. But in some people, the gene stays active, which in turn leads to a faster breakdown of hormones found in contraception, such as estrogen and progestin. The researchers hypothesize that this faster breakdown may increase a woman's pregnancy risk while on birth control, particularly if she is using a low-dose hormonal contraception.

"When a woman says she got pregnant while on birth control, the assumption was always that it was somehow her fault," study lead author Dr. Aaron Lazorwitz, an assistant professor of obstetrics and gynecology at the University of Colorado School of Medicine in Denver said in a statement. "But these findings show that we should listen to our patients and consider if there is something in their genes that caused this [unplanned pregnancy]." [5 Myths About Women's Bodies]

Still, more research is needed to confirm the results and find other genes that may also increase the risk of hormonal contraception failure. But if true, doctors might one day consider genetically testing women for these genes if they become pregnant while on birth control, the researchers said.

The study was published online today (March 12) in the journal Obstetrics & Gynecology.

Birth control and genetics

Hormonal contraceptives are one of the most commonly prescribed medications in the U.S. If used exactly as directed, birth control pills are about 99 percent effective at preventing pregnancy, according to Planned Parenthood. However, about 9 out of 100 women who use birth control pills get pregnant each year, which has been thought to be due to factors such as missed pills.

But few studies have looked at whether a woman's genes affect her response to the medications.

In the new study, the researchers looked at data from 350 healthy women, average age of 22 years, who had a contraceptive implant inserted into their arms for at least one year. The device releases a steady dose of the hormone progestin to prevent pregnancy. The researchers chose to study women with the implant to assure that participants were getting a consistent dose of hormones without the need to remember to take a daily pill (as is the case with hormonal birth control pills.)

The authors found that about 5 percent of participants (18 women) had a variant of the CYP3A7 gene known as CYP3A7*1C and had levels of the hormonal medication in their blood that were, on average, 23 percent lower than participants with a more common gene variant.

In addition, among the 18 people with CYP3A7*1C, five (28 percent) had levels of medication in their blood that were below the threshold of the amount doctors deem necessary for the medication to work properly.

Future studies

The researchers hypothesize that the findings will also apply to women on hormonal birth control pills because hormones in the implant and in the pill are similar, and are broken down similarity in the body, Lazorwitz said. But future studies of women on birth control pills are needed to show this, he said.

Another question for future research will be whether CYP3A7*1C carriers who take hormonal birth control have a higher-than-average rate of unplanned pregnancies.

"At this point, it is too early to say that CYP3A7*1C carriers have a certain risk of contraceptive failure, as [more research] is needed to really quantify what that risk may be," Lazorwitz told Live Science.

In addition, most participants in the report identified as Caucasian or Hispanic/Latina; further study of other women is needed to determine if there may be genes more common in these groups that are also tied to contraception failure.

• Beyond Birth Control: 5 Conditions 'The Pill' Can Help Treat
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• Birth Control Quiz: Test Your Contraception Knowledge

Originally published on Live Science.

You've heard of being "young at heart," but what about young in the brain? A new study suggests that, by at least one measure, women's brains are biologically younger than men's of the same age.

The researchers analyzed brain scans of more than 200 adults, specifically looking at a measure of the brain's metabolism that's known to change with age. They found that, based on these metabolic levels, women's brains appeared about three years younger, on average, than men's brains of the same chronological age.

The findings still need to be confirmed in follow-up studies. But if true, the researchers hypothesize that having a metabolically "younger" brain might provide women with "some degree of resilience to aging-related changes" in the brain. This in turn may help explain why women tend to experience less of a decline in thinking abilities as they age, the researchers wrote in the study, published today (Feb. 4) in the journal Proceedings of the National Academy of Sciences.

Still, much more research is needed. [Men vs. Women: Our Key Physical Differences Explained]

"What we don't know is what it means," senior study author Dr. Manu Goyal, an assistant professor of radiology at Washington University School of Medicine in St. Louis, said in a statement. However, it's possible that it could explain why "women don't experience as much cognitive decline [as men] in later years, ... because their brains are effectively younger."

"Younger" brains

The brain's major fuel source is sugar, or glucose, but exactly how the brain uses glucose changes with age. When people are younger, they devote more glucose to a metabolic process called "aerobic glycolysis," which is thought to help with brain development and maturation, including brain-cell growth. But as people age, their brain undergoes a reduction in aerobic glycolysis, which reaches very low levels by the time they are in their 60s.

But little is known about how brain metabolism differs between men and women. So in the new study, the researchers analyzed brain-imaging scans of 121 women and 84 men who ranged in age from 20 to 82.

They trained a machine-learning algorithm to find a relationship between people's age and their brain metabolism. They found that the algorithm could closely predict a person's chronological age based on their brain's "metabolic age."

Then, they trained the machine-learning algorithm using only men's ages and brain- metabolism data. Next, they entered women's data into this algorithm, and told it to calculate the metabolic ages of the women. They found that, when trained on men's data, the algorithm yielded brain-metabolic ages for the women that were 3.8 years younger than the women's chronological age.

Then, the researchers flipped their analysis: they trained the algorithm on women's data, and told it to calculate the brain ages for men. Doing it this way, the algorithm reported that the men's brains were about 2.4 years older than their actual chronological ages.

Sex differences

Interestingly, the gap between men and women's brain ages was detectable even in young adults in their 20s. "It's not that men's brains age faster — they start adulthood about three years older than women, and that persists throughout life," Goyal said.

The researchers noted that the relative "metabolic youth" of women's brains also parallels the slightly longer life span of women, compared with men.

Still, Goyal noted that the difference between men and women's brain ages was relatively small compared with other well-known sex differences, such as height.

More studies are now needed to better understand this brain-age difference and whether it affects the risk of age-related brain disease, such a Alzheimer's.

Goyal said that the researchers are currently working on another study to test whether the findings play a role in why women don't experience as much cognitive decline as men.

• 10 Things You Didn't Know About the Brain
• 5 Myths About Women's Bodies
• 10 Facts Every Parent Should Know about Their Teen's Brain

Originally published on Live Science.

Archaeologists in Egypt recently unearthed a grim discovery: the skeleton of a young woman dating to about 3,700 years ago who was in the final weeks of her pregnancy when she died.

And she was buried with the unborn fetus still inside her body. 

The tiny skeleton was head-down within the woman's pelvis — a position typically seen in the third trimester — suggesting that she may have died following the onset of labor, officials with Egypt's Ministry of Antiquities said in a statement on Nov 14. [The 8 Most Grisly Archaeological Studies]

An international team of experts from Yale University and the University of Bologna in Italy found the remains. They uncovered the skeletons in a cemetery at the dig site Kom Ombo in Aswan, a city in southern Egypt located about 530 miles (852 kilometers) from Cairo. The graveyard was used between 1750 B.C. and 1550 B.C. by nomadic people who traveled north into the region from Nubia, Secretary General of Egypt's Supreme Council of Antiquities Mostafa Waziri said in the statement.

Other recent discoveries at Kom Ombo include a statue of a cobra-crowned sphinx, engravings of a warrior pharaoh and a stone head representing the Roman emperor Marcus Aurelius.

In the recently excavated gravesite, the woman's body was curled inward and wrapped in a leather shroud. Scientists estimated that she was around 25 years old when she died. Archaeologists inspected her pelvic bones and discovered abnormalities that may have stemmed from an old fracture that was improperly set or that had healed incorrectly. This may have contributed to the woman's difficulties during childbirth, ultimately leading to her death and that of her fetus, Waziri said.

Objects found in the grave included a pottery jar, a container that was colored red on the outside and black on the inside in the style of pots made in ancient Nubia, and beads made from the shell of an ostrich egg. Some unworked shell material was included near the body, possibly indicating that the woman was a bead maker, according to the statement.

All of these funerary objects were likely included to honor the dead woman and to show the respect of her family and loved ones, ministry representatives said.

• The 25 Most Mysterious Archaeological Finds on Earth
• Move Over, 'Tomb Raider': Here Are 11 Pioneering Women Archaeologists
• 10 'Barbaric' Medical Treatments That Are Still Used Today

Originally publishedon Live Science.

Women who trekked across Antarctica in the first-ever all-female expedition broke more than gender norms — they also busted the gender myth that, when it comes to extreme endurance exercise, women are weaker than men.

Sorry men, that's not the case.

"Our findings contain some potentially myth-busting data on the impact of extreme physical activity on women," lead study author Dr. Robert Gifford, of the University of Edinburgh's Centre for Cardiovascular Science, said in a statement. "We have shown that with appropriate training and preparation, many of the previously reported negative health effects [of extreme exercise on women] can be avoided."

The new findings — presented today (Nov. 19) at the Society for Endocrinology's annual meeting in Glasgow, Scotland — contradict some previous research that suggested women experienced more negative effects on their hormone and stress levels than men in response to extreme physical activity. [Men vs. Women: Our Key Physical Differences Explained]

For example, some studies have reported that extreme exertion can suppress female reproductive hormones, impair bone strength and increase levels of stress hormones to a greater degree than in men. But the reasons for these reported differences were unclear.

Into the ice

To better understand the effects of extreme endurance on women, researchers in the new study examined members of the Ice Maiden team, a group of six women from the British army who became the first all-female team to ski across Antarctica. During the two-month journey (from November 2017 to January 2018), the women covered more than 1,000 miles (1,700 kilometers) while pulling 170-pound (80 kilograms) sledges behind them, according to the BBC. The women faced treacherous conditions, including 60-mph winds and temperatures as low as minus 40 degrees Fahrenheit (minus 40 degrees Celsius).

Before, during and after the expedition, the researchers monitored several markers of health, including indicators of stress, hormone levels, body weight and bone strength.

During the expedition, the women lost about 20 pounds (9 kg) of fat mass each, but they did not lose any lean mass, the study found.

In addition, markers of metabolic, hormonal and bone health were largely unaffected by the trip, and those that did change went back to normal shortly afterward.

The findings demonstrate "marked resilience" in hormonal function, stress response and bone strength in women in response to extreme endurance exercise, the researchers wrote in their study abstract.

The researchers note that the women underwent rigorous training before the expedition, which may have helped mitigate any negative health effects.

The researchers plan to further investigate the types of activities and circumstances that contribute to negative health effects caused by physical exertion, and how the effects can be prevented.

"These findings could have important relevance for men and women in arduous or stressful employment, where there is concern that they are damaging their health," Gifford said. "If an appropriate training and nutritional regime is followed, their health may be protected."

• 5 Myths About Women's Bodies
• Female Firsts: 7 Women Who Broke Barriers in Science and Tech
• 10 Amazing Women Who Turned the Tide of History

Originally published on Live Science.

Puritans during the 16th and 17th centuries took a values-driven approach to names. They used their children's monikers to promote their morals, conferring such mouthfuls as "If-Christ-had-not-died-for-thee-thou-hadst-been-damned" and "Fly-from-fornication."

The names are pretty wacky to the modern ear, but a new analysis suggests American parents often do the same thing today — and they have very specific ideas of what values they want to confer on boys and girls. [Sophia's Secret: Tales of the Most Popular Baby Names]

Overwhelmingly, boys get names associated with power, strength and rage, like "Savage" or "Dash." Girls get names associated with joy and beauty, like "Lilac" and "Jubilee." The findings come from a new analysis of newly emerging names by Laura Wattenberg, who runs the naming blog BabyNameWizard.

"It would be reasonable to expect that new names, entering a more egalitarian society, would be more balanced" in their gendered expectations, Wattenberg told Live Science. "But in fact, the numbers just don't bear that out."

Names we value

Wattenberg focused only on "new" word names, or names that appeared in the Social Security Administration database of American babies in 2017, but that were given to fewer than 50 babies in the century prior. She combed through more than 25,000 names that met that criteria to pick out names based on common English words. There were 531. Each name had been given to at least five babies in 2017, and the total list encompassed more than 30,000 kids.

She then sorted each of those 531 new names into categories, ranging from power/toughness (Diesel, Wrangler) and speed (Dash, Blaze) to music (Symphony, Cadence) and joy (Rejoice, Joyful). What surprised her, she said, was that these categories turned out to be massively gendered. [The Most Popular Baby Names in the US in 2018]

Ninety-seven percent of names in the power/toughness category were given to boys. So were 94 percent of the names in the "furor" category, which included such monikers as Riot and Rage. Names invoking speed, weapons, animals and courage were all above 75 percent male.

More balanced was the "reign" category, which included names such as Sire and Empress and was 56 percent male. The "inspiration/potential" category was also relatively gender-neutral, with 44 percent of babies with names like Purpose and Journey being male and 56 percent being female.

On the female side of the spectrum were names with connotations of beauty, love and luxury. Eight-four percent of kids given "beauty" names like Gorgeous were female. So were 91 percent of kids with "love" names like Heart and Adore, and 92 percent of "luxury" names like Cashmere. "Joy" was the most overwhelmingly female category, with 98 percent of names going to girls.

A gender gulf

The gender divide is likely only the tip of the iceberg, Wattenberg said, because her analysis excluded highly gendered names like Maverick, which were too popular to count as "new" but which have recently become increasingly trendy. (More babies born today are named Maverick than Jason, Wattenberg said.) It also excluded traditional gendered names like Grace.

The findings seem to cut across demographics, Wattenberg said. Many word names are popular in certain niches. Color names like Indigo (39 percent male) and Story names like Saga (57 percent male) tend to pop up more in places like Colorado and the Pacific Northwest, she said. Weapons names (83 percent male) are more common where National Rifle Association memberships are more common. Royalty-related names are more typical in African-American communities.

"I'm not trying to criticize any individual family for their name choice," Wattenberg said. "Any individual name is chosen with love for a dozen reasons we might not be able to perceive [from the data]. But when we look at thousands of names and the patterns they form, it always tells us something about our culture."

The "unavoidable conclusion," Wattenberg said, "is that as much as huge strides have been made toward equal opportunity, even loving parents have very different expectations of boys and girls."

Originally published on Live Science.

Physicist Sally Ride, the first American woman in space and the first astronaut to come out as having a same-sex partner, will be getting her own stamp.

Ride, who first launched into space on June 18, 1983 aboard the space shuttle Challenger, was herself an avid stamp collector, her partner of 27 years Tam O'Shaughnessy, said in a statement provided by the United States Postal Service.

"Sally started collecting stamps when she was a girl, and she continued to do so her whole life — especially stamps of the Olympics and space exploration," O'Shaughnessy said. "Sally would be deeply honored to have her portrait on a U.S. stamp."

Ride launched into space twice, in 1983 and 1984, both times aboard the Challenger. She was the third woman overall to reach space, after Soviet cosmonauts Valentina Tershkova in 1963 and Svetlana Savistskaya in 1982. She was the only person to participate in the investigations of both the Challenger and Columbia space shuttle disasters. Her physics career at the University of California, San Diego focused on movement of electromagnetic particles. She co-authored six children's books about science with O'Shaughnessy, and from 1999 to 2000 served as president of Live Science sister site Space.com. She died in 2012, and remains the youngest American woman to travel into space.

Long time NASA illustrator Paul Salmon painted the image used on the stamp. USPS spokesperson Mark Saunders told Live Science that he used a group photo of her first launch crew for inspiration. Ride's stamp pictures her smiling in her astronaut's jumpsuit, which reads "Sally K. Ride" in a patch on her left shoulder. Over that shoulder, the Space Shuttle Challenger lifts off into a blue sky.

Pioneering Women Archaeologists

Pistol-packing Lara Croft returned to theaters on March 16 in the film "Tomb Raider." Croft, played by Alicia Vikander, follows in the footsteps of her adventure-seeking father by traveling to distant lands and exploring remains of ancient civilizations, to piece together the events that led to his mysterious death.

In the context of prior "Tomb Raider" video games and comics — as well as the 2001 film about her exploits — Croft is often referred to as an archaeologist. But in the new movie's story she lacks a scientist's formal training in excavating sites and artifacts. Even the title of the film reflects a colonialist approach to archaeology that is considered highly unethical by archaeologists today, experts told Live Science.

However, there are plenty women who conducted truly groundbreaking archaeological work. Some of their pioneering contributions date back more than a century, and women today continue to forge new paths in the field by challenging how scientists investigate and interpret clues from the past.

Margaret Murray (1863-1963)

British archaeologist and scholar Margaret Murray emerged in the late 19th century as a formidable figure in the developing specialty of Egyptology. In 1899 she became the first female lecturer in archaeology in the U.K., teaching at the University College London, and she led excavations in Malta, Menorca and Palestine, according to a study published in 2013 in the journal Archaeology International. Murray also collaborated with and mentored other women archaeologists, and she supported the civil actions of the suffragette movement in the U.K. — in a passage from her autobiography, "My First One Hundred Years" (William Kimber, 1963), Murray recounted that "young males, even though brilliantly clever, should not pit their wits against an organisation [sic] run by women."

Gertrude Bell (1868-1926)

Born in the north of England, Gertrude Bell was the second woman to graduate from Oxford University in the U.K., a feat she followed up by traveling extensively throughout the Middle East visiting archaeological sites and exploring remote desert locations, according to Newcastle University's Gertrude Bell Archive. Along with her colleague T.E. Lawrence — better known as "Lawrence of Arabia" — she was considered to be one of the foremost European experts on Arab culture in the Western world, during the early 20th century. Bell led archaeological digs in Syria and Iraq, and wrote about her expeditions in highly-respected and popular accounts, according to an exhibit of her books, photos and papers presented at Yale University in 2011.

Gertrude Caton-Thompson (1888-1985)

Wealth and race closely guarded the gateway to archaeology for many decades — and continue to play a part in the field's accessibility — and London-born Gertrude Caton Thompson's privilege enabled her to travel extensively with her family as a young woman, piquing her interest in archaeology with visits to historic sites in Rome and Egypt, according to a profile on Trowelblazers, an organization that offers resources for women and underrepresented groups in archaeological, geological, and palaeontological sciences. Caton-Thompson began her archaeological pursuits at age thirty-three, leading Neolithic and Paleolithic excavations in Egypt, Yemen and Zimbabwe, and her 1929 Zimbabwe dig was excavated entirely by women. Her methods, which included meticulous soil scrutiny and noting objects' positions relative to each other, revolutionized the way that sites were surveyed and studied.   

Dorothy Garrod (1892-1968)

Paleolithic archaeologist Dorothy Garrod's work uncovered important findings about early human origins — including the first evidence of the Middle Stone Age, and the first evidence of dog domestication — and she was also the first to use aerial photographs for archaeological work, according to Michigan State University's Digital Encyclopedia of Archaeologists. Garrod's excavations encompassed 23 sites in seven countries, including Palestine, Lebanon, Iraq, Lebanon, Bulgaria, France, Gibraltar and Great Britain, and she faced the intense physical challenges of field work with humor, writing about an excavation in 1934, "There was considerable consternation as there had been predictions of a cloudburst, an earthquake and the end of the world," according to a diary excerpt published online by the Department of Archaeology at the University of Cambridge in the U.K.

Kathleen Kenyon (1906-1978)

Excavator of the ancient city of Jericho, British archaeologist Kathleen Kenyon chose a career in archaeology after working on Gertrude Caton-Thompson's 1929 Zimbabwe excavation, according to a review of the biography "Dame Kathleen Kenyon: Digging Up the Holy Land" (Routledge, 2008) by Miriam Davis; the review was published in 2008 in the journal Archaeology. Kenyon used a then-novel technique called stratigraphic analysis — peering downward through layers of soil and rock — to better understand how materials accumulate on a dig site, and she was awarded the honor Dame of the British Empire in 1973 for her archaeological and academic achievements, according to Michigan State University's Digital Encyclopedia of Archaeologists.

Honor Frost (1917-2010)

Honor Frost was the first to usher in an era of underwater archaeology, using her skills as a diver to pioneer the excavation and reconstruction of submerged shipwrecks, according to an obituary published by the Guardian in 2010. Frost got her start in archaeology working under Kathleen Kenyon in Jericho in 1957, and she later moved on to explore sites in Lebanon, working with Beirut's Institut Français d'Archéologie. Beginning in the 1960s, Frost incorporated archaeology with her love of deep-sea diving, leading dives and organizing excavations of sites and shipwrecks in the Mediterranean that included the discovery of the lost palace of Alexander and Ptolemy in the Port of Alexandria, the Honor Frost Foundation says.

Gudrun Corvinus (1932-2006)

Paleontologist, geologist and archaeologist Gudrun Corvinus researched and excavated sites across Asia and Africa, and her discoveries informed the understanding of vertebrate paleontology and Paleolithic archaeology, according to an editorial published online in 2008 in the journal Quaternary International. In the 1970s, Corvinus was part of the team in Ethiopia that discovered "Lucy," the partial skeleton of a human ancestor known as Australopithecus afarensis that lived 3.2 million years ago. She later discovered Paleolithic sites in Ethiopia that were determined to be "among the oldest archaeological evidence in the world," and unearthed numerous Paleolithic sites in India, Nepal and Tibet, according to the editorial. 

Theresa Singleton

Writer and archaeologist Theresa Singleton was born in South Carolina and studied archaeology at Oxford University in the U.K. and at Florida State University, where she was a pioneer of historical archaeology in North America, according to an article published in 2014 in the journal Historical Archaeology. Her work uncovered important findings representing the African Diaspora, particularly African-American history and culture under slavery, and life in communities of African-Americans descended from former slaves. In 2014 she became the first African-American recipient of the Society of Historical Archaeology's J.C. Harrington Award — the organization's highest honor — for her contributions to the field, Syracuse University representatives announced in a statement released that year.

Shahina Farid

Born in London to parents who emigrated from Pakistan, Shahina Farid began volunteering on local dig sites when she was still in her teens, and studied archaeology at the University of Liverpool, according to a profile on the Trowelblazers website. Farid has contributed to archaeology projects in Turkey, Bahrain and the United Arab Emirates, as well as in London, and has published more than 40 scientific articles about her work. For two decades, she also served as field director for the Çatalhöyük project — excavation of a Neolithic and Chalcolithic settlement in southern Anatolia dating from about 7,500 B.C. to 5,700 B.C. — where she managed an international team of over 200 scientists, volunteers and students.

Alexandra Jones

Alexandra Jones is a modern ambassador for archaeology. She uses her background in teaching and in historical archaeology to perform outreach on platforms such as the PBS archaeology show "Time Team America," and with her own organization, Archaeology in the Community, which she founded in 2006, according to a Trowelblazers profile. Jones studied biology at Howard University in Washington, D.C., intending to pursue a career in medicine. But she opted for degrees in history and anthropology, and then later received a degree in historical archaeology from the University of Berkeley in California. "I am passionate about empowering future generations through the knowledge and perspectives only archaeology can provide," Jones told Howard University's Howard Magazine.

Whitney Battle-Baptiste

Whitney Battle-Baptiste, an American historical archaeologist of African and Cherokee descent, combines archaeology, academics and activism, and her research examines the intersection of race, gender, class and sexuality as seen "through an archaeological lens," Battle-Baptiste wrote on her website. She is an important pioneer in reconstructing and interpreting life for African Americans through exploration of African American family homesteads and domestic spaces of enslaved Africans. In her book "Black Feminist Archaeology" (Left Coast Press, 2011), Battle-Baptiste proposed improving modern practices of historical archaeology through principles of Black feminism, and challenges the field of archaeology to develop greater sensitivity toward questions of gender and race.

Recommended reading

Can't get enough of the amazing achievements of women in archaeology, past and present?

This list represents just a fraction of the women who revolutionized the field, and who continue to make their mark today. But if you want to dig even deeper, you can find many more examples at the websites Trowelblazers and the Society of Black Archaeologists — pay them a visit to learn more.

Women have a longer life expectancy than men do under normal circumstances, and now a new study from Denmark and Germany reveals that women also outlive men even in the worst of times.

In the study, which took a look back on historical life expectancies, researchers found that women had, on average, a longer life expectancy when facing the harshest conditions — including famines and epidemics — than men did. 

Indeed, the study found that even under extremely harsh and critical conditions, women have a survival advantage, said lead author Virginia Zarulli, an assistant professor at the Institute of Public Health at the University of Southern Denmark. [Wonder Woman: 10 Interesting Facts About the Female Body]

It's not clear why women are the "life-expectancy champions," the study authors wrote, but previous research has suggested that under normal conditions, biological reasons play an important role, along with environmental and behavioral factors.

However, there was little evidence about whether women would have a survival advantage over men under critical, highly life-threatening conditions, Zarulli told Live Science. So, the researchers decided to investigate these situations to tease out whether the differences observed could be explained by biological or environmental factors.

To do so, they analyzed historical data collected between 1772 and 1939 from seven populations facing extreme hardships. Specifically, the researchers looked at data on life expectancy and death rates from groups facing starvation, disease and slavery during times such as the Irish potato famine (1845–1849),  measles epidemics in Iceland (1846 and 1882) and plantation slaves in Trinidad (at the beginning of the 19th century).

All seven of the groups involved in the study had an extremely low life expectancy because of the harsh conditions; one or both sexes were not expected to live longer than 20 years during these crises.

Female survival advantage

In the seven crises analyzed, women survived longer than men: The study found that women outlived men by six months to four years, on average, Zarulli said.

For example, the analysis showed that during the Irish potato famine, women typically lived, on average, 22.4 years, while men lived, on average, 18.7 years. (In the years before the famine, the life expectancy for both sexes was about 38 years, according to the findings.) During a measles epidemic in Iceland in 1882, women lived, on average, 18.8 years, compared with 16.7 years, on average, for men. (In the years before the epidemic, the average life expectancy for women was about 44 years and about 38 years for men.)  

Most of the female advantage in life expectancy during these crises was due to survival differences in infant mortality, according to the researchers. The findings showed that baby girls survived harsh conditions better than baby boys.

Although infant mortality tends to be higher for boys than girls in normal conditions, it was very surprising to find such a striking difference in favor of girls during crises, Zarulli said.

One of the reasons this result was so surprising is that the literature from the time period that the researchers studied suggests that parental attitudes showed a sex preference, usually for baby boys, Zarulli said. "So it is even more remarkable that, despite a potential discrimination against them, baby girls survived more" than baby boys, Zarulli said. (This sex preference meant that parents may have been more likely to seek out treatment for a sick baby boy than for a sick baby girl, for example, or give the boy more food than the girl when resources were scarce.)

This finding offers strong evidence that the reason for a female survival advantage might be fundamentally biological, Zarulli said. That's because behavioral differences among the infants are minimal at this age, and the babies experienced the same environmental conditions, leaving biology as the most likely explanation. [8 Tips for Healthy Aging]

Some biological factors in the female survival advantage include hormones and genetics, Zarulli said. For example, estrogen, the most prominent female hormone, is known to have protective effects on the immune system, and testosterone, the most prominent male hormone, may suppress the immune system, the study authors wrote.

Higher testosterone levels may also cause more reckless behaviors in men, which, in turn, could increase the risk of accidental and violent deaths and thus lower the average life expectancy for men, Zarulli said. (However, this would not affect infant mortality rates.)

"The female survival advantages has deep biological roots, but the role of culture, society and behavior is very important, as well," Zarulli said.

The study was published Jan. 3 in the journal Proceedings of the National Academy of Sciences.

Originally published on Live Science.

More stress in a woman's life may widen her waistline, a new study reveals.

Researchers found that middle-age and older women who experienced more stress from major life events were more likely to develop obesity than women who did not report any stressful events, according to the study, which was presented today (Nov. 13) at the American Heart Association's Scientific Sessions meeting in Anaheim, California.

These findings suggest that psychological stress in women may be linked with  increased odds of obesity, said study author Dr. Michelle Albert, the director of the Center for the Study of Adversity and Cardiovascular Disease at the University of California, San Francisco. [9 New Ways to Keep Your Heart Healthy]

Psychological stress could come in the form of a traumatic life-changing event, such as the death of a child, a life-threatening accident or illness, or a serious physical attack, Albert told Live Science. The stress could also be due to negative life events that occurred within the past five years, such as being unemployed for longer than three months or being robbed or burglarized, she said.

Stress and obesity are both considered risk factors for heart disease, but little is known about the relationship between stressful life events and obesity in women, Albert said.

So, to investigate how stressful events may influence weight changes in women, the researchers looked at data collected from about 22,000 women, with an average age of 72. The women were taking part in the Women's Health Study, a long-running study in the U.S. examining health risks in postmenopausal women. 

About 23 percent of the women in the study were considered obese.

All of the participants answered questions about whether they had experienced a major traumatic event in their lifetime, along with questions about negative life events within the past five years.

Stress and weight gain

The researchers found that women with one or more traumatic events in their lifetimes had a greater chance of being obese that those without any traumatic events.

But it was not just a major stressful experience that was linked to obesity: The study found that the more negative life events a woman experienced, the higher her odds of being obese.

Women who had four or more negative events in recent years were 36 percent more likely to be obese than women with no stressful events. Women with one negative event were 17 percent more likely to be obese, according to the findings.

The study did not investigate why stressful experiences in a woman's life could increase her likelihood of weight gain. One possible explanation is that stress may increase appetite by increasing the production of the hormone ghrelin, often referred to as the "hunger hormone," Albert said.

Stress may also lead to changes in lifestyle habits, such as reduced physical activity or increased alcohol consumption, or it could trigger changes in eating habits, such as snacking more frequently or consuming a poor-quality diet, Albert said. She also noted that emotions may play a role: Feeling stressed out can lead to loneliness or make someone more prone to sleep problems, anxiety and depression. 

One of the limitations of the study is that researchers only looked at a five-year span, so it's unclear at what point during women's lives they developed obesity.

Future studies can examine whether negative life events affect weight gain over time, and if these weight changes are linked with cardiovascular problems, such as heart attacks and strokes, Albert said.

The findings have not yet been published in a peer-reviewed journal.

Originally published on Live Science.

A fertility doctor says that in theory, men could attempt to get pregnant as soon as "tomorrow" thanks to advances in uterus transplant surgeries. But other experts say that such a procedure won't happen anytime soon because many more studies are needed to know whether it could be done safely.

Dr. Richard Paulson, the outgoing president of the American Society for Reproductive Medicine (ASRM), said he thinks it would be possible to perform uterus transplants on transgender women, who are born male and transition to female, according to The Telegraph. Speaking at ASRM's annual meeting, he said he sees no biological reason why the procedure wouldn't work in the male body.

"You could do it tomorrow," Paulson was quoted as saying. "There would be additional challenges, but I don't see any obvious problem that would preclude it. I personally suspect there are going to be trans women who are going to want to have a uterus and will likely get the transplant." [The 9 Most Interesting Transplants]

But other experts point out that the procedure isn't even mainstream for women, let alone men.

Uterus transplants are "still highly experimental," said Arthur Caplan, a professor of bioethics and head of the Division of Medical Ethics at New York University's School of Medicine. This means that the procedure is still being studied for its safety and effectiveness in women, and it is performed only as part of experimental trials.

Because of the additional research needed to understand the risks of the procedure and its effect on the fetus, performing a uterus transplant on a man right now would not be responsible, he said. "Surgically, could you put [a uterus] in a man tomorrow? Yeah, but it would be completely irresponsible," Caplan told Live Science.

Dr. Saima Aftab, medical director of the Fetal Care Center at Nicklaus Children's Hospital, agreed that the fertility treatment field has not yet reached the point where this procedure could be done in men.

"Even for women, there's still a reason for caution" as researchers collect more information about the safety procedure, Aftab said. "[We're] still far away from understanding enough to be able to do this safely in men," she said.

Uterus transplants are a relatively new procedure, with only about a dozen transplants performed so far worldwide. In Sweden, doctors have performed nine uterus transplants, and five of these women went on to successfully get pregnant and have children. But a recent uterus transplant in the United States failed after the organ became infected and had to be removed.

There are a number of risks involved with uterus transplantation, Aftab said. The surgery itself is a complicated procedure that requires the organ to be properly connected to the body's veins and arteries so that it has an adequate blood supply. If there is a problem with the blood supply, the organ will start to die, she said. In addition, people who undergo any organ transplant need to take medications to suppress their immune system so that the body does not reject the organ. But these medications can also increase a person's risk of developing infections.

In men, there could be several added risks. The surgery would be more complicated because the "body's anatomy is not naturally designed for there to be space and blood supply for the womb," Aftab said.

In addition, men do not produce the hormones needed to support pregnancy, so they would need a lot of hormone therapy to allow pregnancy to happen, which could introduce additional risks.

Animal studies likely would be needed to examine the doses of hormones needed to support pregnancy in men and to see whether the blood flow to the uterus is adequate after transplantation, Caplan said.

Finally, if a uterus transplant were to be performed on a person with male anatomy, that person would have to give birth via cesarean section because the male pelvis is too narrow for a baby to pass through, Aftab said. A C-section is also a major surgery that comes with risks. (Women who receive a uterus transplant also have to give birth via C-section because labor may be too stressful for the transplanted organ and because recipients do not feel contractions in the same way women who have traditional pregnancies do, according to Scientific American.)

Right now, the risks of the procedure for someone with male anatomy are so great, "it would be very difficult to think it's something that would be feasible in the short-term future," Aftab said. But it's conceivable that with additional research, doctors would get to a point where the risks are much lower, she said.

Original article on Live Science.

Men appear to be more drawn to women who slightly curve their backs, revealing what could be an evolutionary tactic used by females to imply they are willing to mate, a new study from Portugal finds.

Using 3D models and eye-tracking technology, researchers found that slight changes in posture can affect the perception of a woman's attractiveness. For example, when a woman shifts her hips backward, it creates a curve in the lower back that captivates an observer's gaze, according to the study.

"Increased curvature increases the perception of attractiveness," lead study author Farid Pazhoohi, a psychology researcher at the University of Minho in Portugal, said in a statement. This may explain the lure, for some, of "twerking" and wearing high-heeled shoes.

In the study, researchers created six computer-generated 3D models of a woman's upper body. Each model featured a slightly different posture and was photographed from the front, side and back. The images were then presented to a group of 82 heterosexual male and female undergraduate students, who rated the attractiveness of each model. [7 Beauty Trends That Bad for Your Health]

The models' backs were arched at slightly different angles, with their backsides extended outwards. As the participants analyzed the photos, eye-tracking technology was used to monitor their eye movement.

The more arched a model's back, the more attractive, on average, the participants rated the models.

In addition, both men and women spent a longer amount of time looking at images of the 3D models whose backs were more arched, which suggests that perceptions of attractiveness are largely influenced by this type of posture, the researchers said.

The eye-tracking data also showed that both men and women looked at the rear view of the models much longer than the side or front perspectives. And while women trained their eyes on the models' waist, men tended to focus on the models' hips, according to the study.

"The perception of attractiveness and visual attention to the hip region suggests that 'lordosis,' or the arching of the back, might signal human females' 'proceptivity,' or willingness to be courted," Pazhoohi said in the statement.

Previous studies have found, for example, that the lordosis posture— when the lower back curves in toward the belly — is a sign that animals such as rats, guinea pigs, sheep, cats, ferrets and primates are ready to mate. Therefore, the researchers suggest that a similar signal could have evolved as part of the courting behavior of humans.

"This also might explain why women wear high heel [shoes] and why wearing high heel shoes increases women's attractiveness," Pazhooi said.

The findings were published yesterday (Oct. 25) in the journal Evolutionary Psychological Science.

Originally published on Live Science.

Getting blood from a woman who has ever been pregnant could be risky for men, a new study from the Netherlands suggests.

The study, published today (Oct. 17) in the journal JAMA, found that men who received blood transfusions from previously pregnant female donors were 13 percent more likely to die during the study period, compared with men who received blood transfusions from male donors.

In contrast, men who received blood transfusions from women who had never been pregnant were not at increased risk of death over the study period, compared with men who received transfusions from other men, the study found. And women who received blood from women either with or without a history of pregnancy were not at increased risk of death, compared with women who received blood from male donors.

The findings "are provocative and may — if true — have significant clinical implications," as well as affect the blood donation process and the use of blood in transfusions, Dr. Ritchard Cable, of the American Red Cross Blood Services, and Dr. Gustaf Edgren, of the Department of Hematology at Karolinska University Hospital in Stockholm, wrote in an editorial accompanying the study. However, the results are preliminary, and it's possible that there are alternative explanations for the findings. Therefore, more studies are needed to confirm the results, Cable and Edgren said. For now, the criteria for donating blood should not change, they said. [9 Uncommon Conditions That Pregnancy May Bring]

Previous studies suggested that men who receive blood transfusions from women are at higher risk of death than men who receive transfusions from male donors. But it wasn't clear if a history of pregnancy among female donors affected this link.

In the new study, researchers from Leiden University Medical Center analyzed information from more than 31,000 individuals who received red blood cell transfusions in the Netherlands between 2005 and 2015. People were included in the study only if they received transfusions exclusively from one of three types of donors: male donors, female donors with a history of pregnancy, and female donors without a history of pregnancy. (This means, for example, that patients could not be included in the study if they received blood transfusions from both a male donor and a female donor with a history of pregnancy.) The participants were followed, on average, for a little over a year after their transfusions.

Overall, nearly 4,000 participants died during the study period. For male patients, there were 101 deaths per 1,000 people per year among those who received blood from female donors with a history of pregnancy, compared with just 80 deaths per 1,000 people per year among those who received blood from male donors. This increased rate of death was seen only for men ages 50 and younger.

Among the men who received blood from women without a history of pregnancy, there were 78 deaths per 1,000 people per year — about the same as the rate of death among men who received transfusions from male donors.

For women, there was not an increase in the rate of death among those who received blood from ever-pregnant or never-pregnant women, compared with those who received blood from male donors. [Men vs. Women: Our Key Physical Differences Explained]

Doctors have known that, in rare cases, people who receive a blood transfusion develop a condition called transfusion-related acute lung injury (TRALI), a serious inflammatory reaction in the lungs that can result in death. Antibodies or other immune system factors that women develop in pregnancy could trigger TRALI in male blood-transfusion recipients, the researchers hypothesized.

But the study had limitations. For example, because the patients in the study received blood transfusions from only one type of donor, these patients tended to receive fewer transfusions than the average transfusion patient. (The chances that a patient received transfusions from more than one type of donor increases with the number of transfusions.) So it's unclear how well the findings apply to the general population of transfusion patients (who may be sicker than those in the study), the researchers said.

In addition, the finding of an increased risk of death among men who received transfusions from ever-pregnant women was true only for men ages 50 and younger. "This makes the findings very tentative, and they require validation in other studies," the researchers wrote.

But if future studies do show a similar link, "blood centers and transfusion services will need to mitigate this risk," Cable and Edgren said in their editorial. This might be done by matching donors and recipients based on sex, or by modifying donor blood in such a way as to further remove immune system factors that might be responsible for the link, they said.

Original article on Live Science.