Real competition can drive up testosterone, which boosts libido.

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

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

Every time you cuddle with your children, you're likely to be driving down your testosterone.

Women are very attracted to a low voice because it's linked to testosterone, which for millions of years was a sign that men had very good spacial skills and would have been very good at hunting and finding their way back home.

There exists no culture in which adultery is unknown, no cultural device or code that extinguishes philandering.