A new study has said that women of greater genetic diversity have more sexual partners.
After showing a series of genes linked to the immune system, Western Australia researchers say it can be explained why some women are more sexually successful than others.
The genes are thought to make them more attractive to potential partners.
According to professor Leigh Simmons of the University of Western Australia, having a diverse set of genes was beneficial because it meant a person had more defenses against invading germs.
Such genetic "success" was thought to influence mate choice, the expert claimed.
When searching for a mate, on the subconscious level, people are seeking out someone with different genes from their own to create offspring with a lot of genetic diversity, said Simmons.
He said that a specific group of genes called the major histocompatibility complex (MHC), a driver of the immune system, had previously been shown to influence mate choice, reports The Sydney Morning Herald.
To test if this genetic diversity affected the number of sexual partners a person had, the research team assessed the genetic variability of 74 females and had them fill in a questionnaire about their sex life.
After removing the bias associated with age and sexual attitudes, Simmons found those women who had more genetic diversity in their MHC complex reported more sexual partners over their lifetime.
The number of partners was predicted by genetic variability, said Simmons.
The study has been published in The Journal of Animal Behaviour.