A woman of 40 or 50 or 60 can take estrogen replacements, get facelifts, spend her money in bars.

When chimps threaten, they open their mouth and show their teeth. It's a little like waving a knife in front of you. It's very primitive, and therefore bizarre.

The Internet lets women use words, which is their natural tool. Little girls speak in more complex, grammatical sentences than little boys do, and women never lose that superiority in verbal ability.

Any kind of novelty or excitement drives up dopamine in the brain, and dopamine is associated with romantic love.

The brain was not built to walk into a bar, where you know nobody, and start a conversation. That's not the way humanity has courted.

Like most animals, we're wired to associate height with power.

Women have a better sense of smell than men do, and it's even sharper in the middle of their menstrual cycle, when estrogen levels peak and women are more likely to be deciding whether a man's attractive.