Can you guess which dopamine receptor genes they have? Credit: Adam Judd
Are you unhappy with your ability to function sexually? Do you lack interest in sex or find it difficult to become aroused? Are you unsatisfied with your orgasms? If so, you may be genetically predisposed to have a moderate to low sex drive.
Israeli researchers published a study online in the April 18th issue of Molecular Psychiatry suggesting a link between a dopamine receptor gene and human sexual desire, arousal and function. They conclude that one gene variant found in about 60% of the population may lead to a more subdued sex drive while another, found in about 30% of the population, contributes to higher sexual desire, arousal and function.
"This rarer variant that seems to give the higher performance or desire has been associated by us and by some other people with things like novelty seeking, a sort of extroverted personality, as well as attention deficit in children and in adolescents," said Hebrew University psychology professor Richard Ebstein, an author of the study.
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Ebstein's team studied 150 university students, each of whom donated a DNA sample so the researchers could catalogue their D4 receptor gene, which controls the number of dopamine receptors in the brain. (Dopamine, a naturally produced neurotransmitter, is typically associated with feelings of pleasure and enjoyment.)
The subjects were scored on their sex drives based on their answers to a survey with questions such as "Approximately how often do you get sexually aroused?" and "How satisfied are you with the frequency of your sexual intercourses?"
Comparing the questionnaire scores with the gene variants, the researchers found that subjects with the less common variant self-reported significantly higher sex drives, which was somewhat surprising because that variant apparently coded for fewer dopamine receptors in the brain.
"In general you would have thought that more dopamine, or more dopaminergic activity, would give you more sexual activity, " Ebstein said. "If you give an animal something that stimulates dopamine, it facilitates sexual behavior."
The gene-to-sex drive correlation was nearly identical in males and females, although Ebstein noted the self-reports confirmed that in terms of "how horny people are," men score higher than women.
This study is the first to provide data linking common genetic variations and differences in human sexual phenotype, according to Ebstein. However, other papers have indicated a general link between genetics and sexual function. For example, one study of twins found that difficulty in reaching a female orgasm has a 45% heritability.
Keele University epidemiologist Kate Dunn, the lead author of the female orgasm paper, notes that genetics is only one component of human sexuality.
"Genetics are very unlikely to explain everything," Dunn said. "Previous research has shown that there are many other social and psychological influences on sexual problems and sexual behavior."
Ebstein said his discovery of a genetic component to sexual function could give solace to people unhappy with their libidos.
"It may be that people shouldn't worry about whether they don't have much desire or interest," Ebstein said. "They don't have to pay much attention to popular culture because they know they're just like a lot of other people."