Cited research: Evolution doi:10.1111/j.1558-5646.2010.00989.x (2010)

Sexual promiscuity has been thought to be an important contributor to the evolution of the immune system, owing to the link between sexual activity and disease exposure. Gabriela Wlasiuk and Michael Nachman at the University of Arizona in Tucson have now found evidence for this at the genetic level.

They estimated the molecular evolution rate of proteins coded by 15 immune-defence genes in several primate species, and found a weak but statistically significant correlation with female promiscuity.

The researchers suggest that higher levels of promiscuity may increase exposure to sexually transmitted diseases, thus increasing the potential for natural selection to act on the immune system and drive the evolution of immunity genes.