Genetic Causes Of Infidelity Found In Twins Study
This is excerpt from an intersting blog article about infidelity we located at Future Pundits
A comparison of the sexual histories of 1600 identical and non-identical twins found that genetic variations play a large role in influencing the tendency to infidelity among women.
“We found that around 40 percent of the influence on the number of sexual partners and infidelity were due to genetic factors,” Professor Tim Spector, director of the Twin Research Unit at St Thomas’ Hospital in London, told a news conference.
Identical twins whose twin has strayed have twice the normal chance of straying.
The findings mean that someone with a philandering twin is far more likely to philander themselves. The average risk of female infidelity is about 22%, says Spector, but those with an unfaithful identical twin have a risk of 44%.
Women tend to stray to hook up with higher status men.
The study, which was published in the journal Twin Research, suggests that a genetic predisposition towards female infidelity may have evolved because it was important in allowing women married to “low status” men surreptitiously to become pregnant by “high status” men.
“If female infidelity and number of sexual partners are under considerable genetic influence, as this study demonstrates, the logical conclusion is that these behaviours persist because they have been evolutionary advantageous for women,” the researchers write in their scientific paper.
Female straying for higher status males offers a selective advantage that could have been selected for.
From an evolutionary perspective, a woman’s best short-term strategy would be to clandestinely pursue men with better genes.
Prof Spector points out that women tend to have affairs with men of higher status than their husbands. However, the system would break down, he said, if “everyone was unfaithful, because there would be no pair-bonding”.
Three chromosomes were identified in this study as likely locations for genes that influence the odds of monogamy.
It lends strong support to theories advanced by evolutionary psychologists such as Steven Pinker, of Harvard University, who argue that human sexual behaviour is at least partly determined by natural selection and our genes.
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Professor Spector’s team did not identify any particular gene that contributes to a tendency to infidelity, though they did pinpoint three regions on chromosomes 3, 7 and 20 that might harbour such genes. He believes that there are between 50 and 100 genes that contribute to a tendency to infidelity.
