Real competition can drive up testosterone, which boosts libido.

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

Kissing is not just kissing. It is a major escalation or de-escalation point in a powerful process of mate choice.

We all have restlessness in long-term relationships.

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.

Men tend to be hierarchical, but women are driven to make lateral connections so they can cooperate.

Haiti is the poorest country in the western hemisphere; some say the poorest in the world.