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.

Saliva has testosterone and estrogen. When you kiss, you're having a chemical experience.

Experiences shape the brain, but the brain shapes the way we view experiences, too.

Good-looking people are always looking for other good-looking people.

In America, we are demanding everything from our marriage.

It's in our genes, we were built to wander.

For so many generations, a woman's only career path was to marry well and to marry up. Those days have changed.