A new study has revealed that being unfaithful to partners may be genetic , as some are genetically programmed to cheat in a relationship.
Researchers at Binghamton University have revealed that the propensity to cheat could very well be in the DNA.
In a first-of-its-kind study, a team of investigators, led by Justin Garcia, has taken a broad look at sexual behaviour, matching choices with genes and has come up with a new theory on what makes humans 'tick' when it comes to sexual activity.
The biggest culprit seems to be the dopamine receptor D4 polymorphism, or DRD4 gene. Already linked to sensation-seeking behaviour such as alcohol use and gambling, DRD4 is known to influence the brain's chemistry and subsequently, an individual's behaviour.
"We already know that while many people experience sexual activity, the circumstances, meaning and behaviour is different for each person," said Garcia.
"Some will experience sex with committed romantic partners, others in uncommitted one-night stands. Many will experience multiple types of sexual relationships, some even occurring at the same time, while others will exchange sex for resources or money. What we didn't know was how we are motivated to engage in one form and not another, particularly when it comes to promiscuity and infidelity," he added.
Gathering a detailed history of the sexual behaviour and intimate relationships of 181 young adults along with samples of their DNA, Garcia and his team were able to determine that individual differences in sexual behaviour could indeed be influenced by individual genetic variation.
"What we found was that individuals with a certain variant of the DRD4 gene were more likely to have a history of uncommitted sex, including one-night stands and acts of infidelity," said Garcia.
"The motivation seems to stem from a system of pleasure and reward, which is where the release of dopamine comes in. In cases of uncommitted sex, the risks are high, the rewards substantial and the motivation variable - all elements that ensure a dopamine 'rush'," he added.
According to Garcia, these results provide some of the first biological evidence that at first glance, seems to be somewhat of a contradiction: that individuals could be looking for a serious committed long-term relationship, but have a history of one-night stands.
The data suggested it was also reasonable that someone could be wildly in love with their partner, commit infidelity, and yet still be deeply attached and care for their partner. It all came back to a DRD4 variation in these individuals. Individual differences in the internal drive for a dopamine 'rush' can function independently from the drive for commitment.
"The study doesn't let transgressors off the hook," said Garcia.
"These relationships are associative, which means that not everyone with this genotype will have one-night stands or commit infidelity. Indeed, many people without this genotype still have one-night stands and commit infidelity. The study merely suggests that a much higher proportion of those with this genetic type are likely to engage in these behaviours," he added.
This study also provides further support for the notion that the biological foundations for sexual desire may often operate independently from, although absolutely linked to, deep feelings of romantic attachment.
The study is published in the current issue of Public Library of Science's PLoS ONE journal.