Genes fuel sex drive

Israeli scientists have uncovered new evidence that differences in sexual drive and desire can be correlated to particular gene variations. The team combined research into a recently discovered specific dopamine receptor (DRD4), which has been shown to induce penile erection through a central mechanism in rats, with a questionnaire investigating participants' perceptions of their own sexual desire, arousal and function. The researchers hope that there may be far-reaching effects based on the finding that differences in sex drive may be quite normal and not necessarily the result of dysfunction. There is also the possibility that new pharmacogenetic strategies could be developed in this area.

The researchers - a collaboration between the psychology department at the Hebrew University and the psychiatry division of Ben Gurion University - examined both DNA from and questionnaires provided by 148 non-clinical male and female students. The results showed a correlation between different D4 receptor gene variants and the students' self reports about their sexuality, with three main variants linked to heightened, depressed or 'normal' sexual awareness. It was found that around 30 per cent carried the variant for heightened arousal, compared with 60 per cent carrying the depressed variant and 10 per cent falling into neither category. The researchers believe that the variant that triggers increased desire is a relatively recent mutation appearing only 50,000 years ago, as humans began to spread out of Africa.

The report, published in the journal Molecular Psychiatry, challenges the traditional view that differences in human sexuality are the result of learned behaviour or psychology. The D4 receptor triggers a reaction to the neurotransmitter dopamine, commonly associated with pleasurable experiences. Professor Ebstein, lead researcher on the study and director of the Scheinfeld Center for Human Behavioural Genetics at the Hebrew University, said 'For the first time a specific gene variant has been linked to human sexual desire, arousal and function. These findings suggest that some aspects of human sexual behaviour are hard-wired and that individual differences in sexuality are partially due to specific genes. Such genes may in the future become the targets of specific drug treatments for specific problems'.