People live for love. They kill for love. They die for love. They have songs, poems, novels, sculptures, paintings, myths, legends. It's one of the most powerful brain systems on Earth for both great joy and great sorrow.

Today, most women are surrounded by ingenious gadgets. They don't grow the peas or raise the chicken that they serve for dinner; instead they hunt and gather in the grocery store. They go through catalogs or department stores to buy clothes instead of shearing sheep, carding wool, and weaving cloth for skirts and coats and blankets.

Women spend their lives trying to look good for men. So a woman who feels she's sending the right visual signals is pleased with herself.

A hundred years ago, if you had a child out of marriage, you'd be a social disgrace. Today women feel comfortable enough economically and culturally to bring up a child without a recognized commitment from a man.

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

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.

When you fight, anger drives up testosterone in both men and women.