Many different environmental factors affect a person’s sex drive—music, stress, food, anger, and depression can all shut down or heighten that lovin’ feeling. New research suggests that our genes may also shape our desires, arousal and sexual function. In the May 2006 issue of Molecular Psychiatry, Israeli researchers from the Ben Gurion University of the Negev and Hebrew University report a connection between a gene known as DRD4 and sexual desires of nearly 150 college students. The students filled out questionnaires about their sexual desire, arousal and sexual function, and then tested for variations in their DRD4 gene.

DRD4 is a gene that codes for a dopamine receptor protein. Dopamine is a chemical that affects our feelings of pleasure when it binds to the receptor proteins poking out of the surfaces of our brain cells. Researchers found that students with one type of mutation in this gene had very strong sex drives, while students who had a different type of mutation expressed very limited sexual desires. This genetic version of a cold shower is thought to occur in about 60 percent of the world’s population.

Researchers think the genetic variation for an increased sex drive was a relatively recent evolution (about 50,000 years ago, when people where just starting to migrate out of Africa). Because it’s newer, it is also less common. Approximately 30 percent of men and women carry this sexier version of the DRD4 gene.