The Moral Code of Chinese Sex Workers

A researcher immersed herself in the “sisterhood” of China’s female sex trade—and came away with an appreciation of its rules of conduct.

Nature’s Most Creative Copulators

Why have humans taken mammalian sex to a whole new level?

The Sexual Allure of Simplicity

Is the return to a simple life a “new” way to advertise our good qualities? An evolutionary perspective says yes.

When Did Sex Become Fun?

Sexual reproduction has been around for 2 billion years. But when did sex for pleasure arise? And how much did penises have to do with it?

Between Male and Female

Can television shows like Orange Is the New Black and Faking It push forensic anthropologists—and the rest of us—to rethink our categories of biological sex?

Labor Pains and Helpless Infants: Eve or Evolution? (Part 2)

Anthropologists often use an idea called the “obstetrical dilemma” to explain why humans have helpless infants, but there is mounting evidence that this explanation is insufficient. Part II.

Skeleton Sex Pots

An unusual container produced by the Moche civilization of Peru raises many questions about their society—and our own views of sex.

Surprise! Semen Is Required

How putting a tiny pair of pants on an 18th-century frog was one step on the long road to solving the puzzle of reproduction.

When Sperm Compete, Nature’s Call Leads to Bigger … Testicles

Success in the living world is all about reproduction. Sperm competition has caused primate testicle size to increase.

The Half of the World That Doesn’t Make Out

Surprisingly few societies have romantic kissing in their repertoire.