Sex

A monkey was recently seen performing sexual actions on the backs of female sika deer on Japan's Yakushima island.

Accusations of infidelity are quite common in the 2016 election — but how common is infidelity, really?

In two widow spider species, males deploy an ingenious strategy to avoid being cannibalized during sex.

A new study pulls the sheet off millennials' sex lives, revealing that there isn't as much going on as you might expect.

When a woman is more attractive, a man is less likely to intend to use a condom with her, a new study finds.

Virgins have the lowest divorce rates, while women with exactly two sexual partners have historically had the highest odds of divorce.

After the June 12 shooting in Orlando, many gay and bisexual men who wanted to donate blood were unable to do so.

Casual hookups may not be good for your love life.

When it comes to sex with a much bigger mate, one type of spider has the problem licked.

Contrary to what daytime talk shows might have you believe, men are rarely hoodwinked into raising children who aren't their own, according to several recent studies.

When a group of researchers crossbred cichlids to learn about their genetics, they discovered an unusual development in one of the hybrid females.

Sex among primates and certain mammals is thought to provide pleasure for the participants. But for many animal species, sex is anything but pleasant.

Astrophysicist Tyson tweeted: "If there were ever a species for whom sex hurt, it surely went extinct long ago." Sorry Dr. Tyson, evolution don't care if sex is painful.

For male nursery-web spiders, bondage during mating can be a matter of life and death.

A female water snake in Missouri can do something that no human woman can (no matter how badly she might want to).

Sex does not increase heart attack survivors' risk of having another attack, except in rare cases, a new study finds.

We may never know exactly what drove millions of men and women in committed relationships to log on to AshleyMadison.com to find lovers, but most cheaters fall into two categories, science shows.

Addyi, the new libido-enhancing pill for women, was approved by the FDA, but many health care professionals are still skeptical about whether women really need the drug.