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/ Source: TODAY contributor
By By Bob Considine

Swedish researchers have linked a so-called “monogamy” gene with the relationship behavior of men and their partners — but that doesn’t mean those who have it are destined to be unfaithful, according to sex and relationship experts.

“This is just one component to a much larger puzzle,” Dr. Laura Berman told TODAY co-host Matt Lauer on Wednesday.

“It has to do with whether you were raised in a family where infidelity happened, whether you were socialized to be comfortable expressing emotions … Remember, this gene really wasn‘t specifically about infidelity. It was about bonding — and men who are bonded to their partners, of course, are less likely to cheat.”

Still, the findings by researchers at the Karolinska Institute in Stockholm suggest that there could be some scientific roots to some men’s tendency to stray. Their study found that men who carry one or two copies of a gene variant called “allele 334” were twice as likely to have had marital or relationship woes in the past year than those who don’t have it.

“The incidence of allele 334 was statistically linked to how strong a bond a man felt he had with his partner," lead researcher Hasse Walum said in a statement.

But while the study may have some women wondering if they should test potential partners to quantify their level of commitment, NBC News chief medical editor Nancy Snyderman said you can’t determine a man’s tendency to stray by his genetic makeup.

“It’s a fascinating part of the human genome,” Snyderman told Lauer. “[But] there’s no cheek swab out there for young men who are coming to our daughters’ doors.”

Telling results

The study surveyed 550 twins and their partners or spouses, all in Sweden. Eighty-two percent of the couples were married, while the other 18 percent were living together.

Allele 334 is found in four of 10 Swedish men, according to the researchers. It controls the production of vasopressin, a hormone found in mammals that had been linked to mate stability in prairie voles (a type of rodent) in earlier studies.

Walum said men who had the variation received low scores on the bonding test and were not as likely to be married as men who lacked it. Furthermore, 15 percent of men without the allele reported serious marital discord in the past year, compared to 34 percent of men who had two copies of the allele.

And the happiness of partners of those with and without the variant was equally consistent.

“Women married to men who carry one or two copies of allele 334 were, on average, less satisfied with their relationship than women married to men who didn't carry this allele,” Walum said in a statement.

In a separate segment on TODAY, Dr. Phil McGraw told Natalie Morales that the findings should not be dismissed.

But during her segment, Snyderman pointed out that evolution may also be a factor. “Let me take you back a few thousands of years, when a man needed to procreate to have a large family to take care of him, to make his own armies,” she said. “The idea of one-night stands, biologically sort of rooted in our history, [made] sense. But as we have proceeded in society and social norms have taken place, perhaps those partner chromosomes have adapted.”

Litmus test?

If so, what is to be made of the results of the Swedish research, which were published Tuesday in Proceedings of the National Academy of Sciences?

Even Walum indicated that the specified gene will have only a small influence on men’s behavior. Yet there are many alarming statistics out there: Twenty-two percent of married men stray from their partners at least once during their marriage, and 53 percent of American marriages end in divorce.

Berman, an assistant clinical professor of psychiatry and obstetrics/gynecology at the Feinberg School of Medicine at Northwestern University who has been working as a sex educator and therapist for 18 years, cautioned women that trust is a more complex matter than screening for genes.

“The idea that they could know, ‘Can I really trust a man?’ — if that were possible, that would be great. But the bottom line is, that’s not going to give you the answers.”

McGraw also wondered aloud whether women should consider a genetic screening of their potential husbands: “Should you [say], ‘OK, I want to know what your finances are. I want to know what your religion is. I want to know what your allele status is?’ ”

But ultimately, McGraw said, genetics are not a free pass for inappropriate behavior.

“Lots of guys may say, ‘Hey, it’s my genes, what can I say?’ ” he said. “But it’s not an excuse. Biology is not destiny. It just means that you’re predisposed.

“Genetics seldom determine what is going to happen — only what can happen.”