Researchers are finding a correlation between genes and men who cheat on their mates.
The gene variant is present in 2 out of every 5 men, and if you have it, the study shows you're more likely to be prone to marital dysfunction. If you have two copies of the gene variant or allele, you're twice as likely.
The allele studied by the Karolinska institute in Stockholm, regulates the activity of a hormone in the brain, and can affect a man's attitudes toward fidelity and monogamy.
If a man lacks the gene variant, they're more likely to be a devoted mate.
More than 1,000 heterosexual couples were studied. The scientists looked at men because the hormone is known to play a larger role in their brains than in women's brains.
The study found that the gene also seems to predict whether women describe their mates as close or distant; and whether the men are more likely to marry, or simply live with their mates.