The variability in human sexual behavior is high and not yet clearly understood. Furthermore, the likely genetic basis remains unexplored. The current study examines the association between the dopamine receptor gene (DRD4) and certain sexual behaviors, specifically outside of committed relationships. It was found that people having at least seven repetitive codes in a specific region of the dopamine receptor gene (otherwise known as 7R+), showed instances of random sexual relations and disloyalty. It was also deduced that the individual differences were traced back to an incentive-to-reward cycle in the brain.
The background of casual sexual relationships and the probable role of genetic influence on motivating such behavior need to be evaluated. This study considers “promiscuity” as a single instance of uncommitted sex and “infidelity” as continued sexual interaction outside a committed partnership. Promiscuity leads to dangers of diseases, unnecessary pregnancies and losing partners. However, infidelity could bring about beneficial genetic diversity. A study of manifestations of such behavior in identical twins established the genetic link to such behavior. It has been found that the dopamine receptor gene (or a part of it with seven or more repetitive sequences) corresponded with a desire of sensation or arousal or subsequent reward. One variant of the dopamine transporter gene is known for a high reward-seeking tendency. This directly translates to more partners, irrespective of previous relationships.
* A self-reporting, confidential survey was conducted among 181 participants, collecting information on sexual behavior, inclinations and choices. A parallel monetary quiz helped identify impulsive nature and the extent of urge to seek rewards.
* DNA samples for genetic analysis were taken from oral washes.
* Grouping of phenotypes was done and correlated with genotypes and statistical findings from the survey answers.
* The 7R+ group reported double the occurrence of promiscuous behavior, as compared to the 7R- group; the fidelity percentage ratio was 50 to 22 respectively.
* In instances of disloyalty, the 7R+ group was involved with 50 percent more out-of-relationship partners.
* A given ancestral subset or age or gender did not vary the observed trend.
* The craving for immediate small rewards was recorded by noting nicotine-dependence and smoking patterns. But the results clearly proved no mapping between this inclination and promiscuity/infidelity in sexual behavior.
Unaccounted variables might have played a part in these results, such as more frank responses to the survey from the 7R+ group. It is also probable that variability in intrinsic mating features like attractiveness impacted the results. The inferences from this study need repeated confirmation and subsequent understanding of the physiological and psychological aspects.
This experiment was the first of its kind to approach the genetic underlying mechanisms for sexual behavior. The DRD4 gene has been known to be associated with numerous psychiatric conditions like attention-deficit hyperactivity disorder (ADHD), impulsive decision-making and enhanced yearning for dopamine-related rewards like food/some drugs/nicotine. This tendency for craving could lead to promiscuity and infidelity, in terms of sexual behavior. However, a shift in the social outlook towards acceptance of uncommitted sexual interactions could encourage such behavior in young adults. Hence, discretion is required before blaming the DRD4 gene for cheating. In other words, all other probable reasons for infidelity/promiscuous behavior must be examined to arrive at the correct conclusion.
For More Information:
Associations between Dopamine D4 Receptor Gene Variation with Both Infidelity and Sexual Promiscuity
Publication Journal: PLoS ONE, November 2010
By Justin R Garcia; James MacKillop
From the Binghamton University, Binghamton, New York and University of Georgia, Athens, Georgia
*FYI Living Lab Reports Are Summaries of the Original Research.