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

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.

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

Your sweetheart calls you by another's name. His eyes linger too long on your best friend. He talks with excitement about a girl at work. And the fire catches. Jealousy - that sickening combination of possessiveness, suspicion, rage, and humiliation - can overtake your mind and threaten your very core as you contemplate your rival.

Research shows that couples who have a lot of similarities, including intellectual compatibility, end up staying together.

Any time you choose not to hide your tattoo, you're limiting your social sphere, because they're not popular in big business.

People have been looking for love potions since hunter-gatherer societies.