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

Barriers tend to intensify romance. It's called the 'Romeo and Juliet effect.' I call it 'frustration attraction.'

We still have community, but we don't seem to have local community. Even in a small town where you know your neighbors and your mother's down the street, they're not in arm's length.

Most of us make up our minds in the first three minutes of meeting someone whether there's a potential for a relationship.

Along with our many human propensities, we evolved a huge cerebral cortex with which we make decisions.

There is more and more data indicating that there is a biological basis to your political views.

Today, American women bear an average of 2.2 children that live to adulthood. Across most of Europe, women bear even fewer young.