Not long ago, Hasse Walum, a handsome post-graduate at the Karolinska Institute in Sweden, decided to study the association between a particular gene for what is called a vasopressin receptor and relationship stability. He analyzed the responses of over 550 twins and their partners to questions, some of them intrusive, about their relationships: How often do you kiss your mate? “Have you ever regretted getting married/moving in?” “Have you discussed a divorce or separation with a close friend?” “Rate your degree of happiness in your relationship on a scale of 1-7.”
Walum then sampled the men’s DNA. Getting DNA from the men was simple. You don’t need blood to have access to another person’s genome, just saliva, which the men submitted in a mouth swab.
What Walum discovered was stunning. Focusing on one particular vasopressin receptor gene variant, allele 334, he found that the more copies of it a man had, the weaker his bond with his partner. Men who lacked the gene variant were generally happiest in their relationships — only 15 percent of them had a crisis. Men with one copy were slightly more likely to have marital problems. And men with two copies were, on average, twice as likely to have had a relationship crisis in the past year than men who didn’t have the variant — meaning that 34 percent of them, or one in three, were headed toward a break up. Their partners agreed. Women whose partners carried one or two copies of the allele 334 variant were generally less satisfied with their men, probably because they generally scored as less affectionate than other guys.
Walum also found that men with two copies of the variant were nearly twice as likely not to marry their partners and mothers of their children as men who had no copies of the variant. This suggests that there is something slightly different about the vasopressin receptors in the brains of men who struggle in their roles as partners and fathers. These men may have more difficulty bonding with other people, including their wives and kids.
I imagine that some of you are now scheming to get an allele 334 test for your man. Of the more than five hundred women who responded to my online poll on this topic, nearly 65 percent said they would test their man if given the option.
Ladies, there’s a caveat here, of course. Even if there’s a correlation between this particular gene variant and a man’s behavior, it doesn’t account for all men. Just as the “god gene” and “gay gene” are met with skepticism in the scientific community, so is the “cheating gene.” Even within Walum’s study, there were men with two allele 334 variants who were happy husbands and fathers, and there were men without the variant who were miserable in their relationships. The statistics apply to populations, not individuals, who are also influenced by a other factors — parental role models, partner choice, opportunity to cheat, past loves, age, life satisfaction, religion, hormone levels, and so on.
A two-allele man may become a number one husband under the right circumstances.