Sally Law

More active play with baby boosts dad's "love hormone."

Even for the elderly, men have more sex than women.

As 2009 comes to a close, LiveScience looks back at the year's nine most intriguing sex lessons.

Men who can regulate their sexual arousal can also control their other emotions.

New research has found that spirituality has a greater effect on the sex lives of young adults.

Gender-reassignment surgery addresses larger issues of gender, sexuality and sexual orientation.

Unsexy as it sounds, there are some health risks and practical concerns associated with summertime sex.

Men who ate antioxidant-rich fruits and vegetables have better rates of sperm movement, ejaculate volume, and sperm concentration.

The tenets of sexual health need to be addressed and upheld, and political and religious leaders should lead the charge.

A new study finds that the involvement of fathers lowers risky sexual behavior in teenagers.

While oral contraceptives are effective in reducing the risk of unwanted pregnancy, its effects on the human body – both good and bad – have been cause for debate.

A recent study discovered that men feel guiltier following sexual infidelity, while women feel guiltier after emotional transgression.

A new study on reproductive success finds that humans don’t always conform to the roles of "promiscuous" males and "selective" females.

A recent study finds that not only do some men prefer overweight women, but that they also find a wide range of body sizes attractive.

How well do "friends with benefits" relationships work?

A new study finds that when it comes to personality, people seek partners with their same qualities.

Research suggests women's pain during sex should be reclassified as a pain disorder rather than a sexual dysfunction.

Women who pay too much attention to their performance during sex could be inhibiting sexual desire.

Sex in advertising? Women aren't buying it.

What do men want in a woman? Brains? Beauty? Vacuuming prowess?

Both men and women are able to gauge a man’s interest in a woman, but are equally baffled when it comes to figuring out if a woman is interested in a man.

A new study finds that the brains of hormonal women respond to men with overtly masculine facial features.

Extended courtships allow females to screen for potential providers, while males can prove they're suitable.

Even updated, "The Joy of Sex" is by no means a scientific treatise: its most popular section will likely remain "Main Courses."