Why do people of different sexes vary in their susceptibility to various diseases? New research points to body fat and the immune system.

Having boys or girls is essentially random and doesn't depend on the parents' genes, researchers report.

An expert busts a few chocolate myths, including whether women are more into it, and whether it boosts romance as an aphrodisiac.

Young sexual minority men need education about the risks, symptoms, and prevention of human papillomavirus (HPV), new research shows.

Legislation has deemed pornography a public health crisis, but experts say there's no evidence to back that up.

Protein levels in a drop of blood can accurately predict someone's age, researchers say. The discovery sheds new light on how we age differently.

Most research on low libido among older women has focused on hormones. Interviews indicate other factors.

Same-sex behavior in animals is not only "not costly" from a natural selection perspective, but it also may have important benefits.

Cisgender children tend to gravitate toward the toys, clothing, and friendships stereotypically linked with that gender. Transgender children do the same, research finds.

"[C]hildren's brains function similarly regardless of their gender..." according to a new neuroimaging study on math ability in boys and girls.