The Science Of Infidelity: Why Women Are More Likely To Cheat On Men

by Eve Stern

Okay, I know you might be outraged, but just stay with me for a minute.

New research shows women may be more likely to be the culprits of infidelity than men.

It’s not that women are more likely to cheat than men per se, but biologically and genetically, we possess different features that vary our behaviors.

This research is colossal because ideologically, we tend to assume men are the more likely culprits due evolutionary implications.

From a “survival of the fittest perspective,” it makes slightly more sense that they would spread their seed to as many women as possible.

Women, on the other hand, don’t share this evolutionary ideology, and are more so on the opposite spectrum: supposedly choosing most carefully a mate who we believe could provide and take care of us, although this obviously isn’t always the case.

Despite this, women may be more prone to cheat instead due to their hormones and genes. Richard Friedman lets us in on this secret in his op-ed, “Infidelity Lurks in Your Genes.”

The key word is vasopressin. Women who carry a type of genetic mutation in the receptor for this hormone are more likely to engage in infidelity, so maybe it’s not their fault?

The suggestion is carried by a recent study by a psychologist, Brendan P. Zietsch, at the University of Queensland, Australia.

Dr. Zietsch examined the link between promiscuity and the receptor genes of important hormones, like vasopressin and oxytocin.

Ever heard of oxytocin? If not, look it up, or better yet, read Louann Brizendine’s "The Female Brain." It will clue you in on exactly how our bodies and brains work for us ladies.

But, back to oxytocin, it’s like the mitochondria of our feelings or, in other words, it’s really goddamn powerful.

It’s a hormone that also acts as a neurotransmitter in the brain and essentially increases our drive to romantically pair up.

It’s released on many occasions, but most evidently during sex. Vasopressin is another hormone, similar in nature, which has a great force on social behaviors associated with bonding, like trust, empathy and, of course, hooking up.

In his study, Dr. Zietsch examined the link between the wandering eye and variations in the oxytocin and vasopressin receptor genes in thousands of people who had been in a relationship for at least a year.

Why? Because mutations of the vasopressin receptor could also mutate one’s own sexual behavior.

Through the study, he found 6.4 percent of women, compared to 9.8 percent of men that year, had two or more sexual partners.

The caveat is Zietsch’s study discovered there was an association between five different variants of the vasopressin receptor gene, which was only found in women who participated in infidelity.

Thus, we ask, does this mean 40 percent of women who partake in a variation of infidelity can blame their genes?

For years, we’ve know how oxytocin and vasopressin are associated with relationships, both found in the opposite end of the infidelity pool.

Oxytocin is the reason one-night stands for women tend to be more difficult.

The hormone supplies emotional bonding, AKA feelings, so when women have sex, we release loads of it. Annoying, right?

This is why more often, women have sex with specific partners and biologically, we’ll want more than sex.

Another study from Hasse Walum at the Karolinska Institutet (Institute) in Stockholm found that in women, there is strong association between one variation of an oxytocin receptor gene and marital antagonism, or lack of fondness for one’s partner.

Similarly in men, this same predicament (of a lower marital discord) occurs, but in regard to a variation of the vasopressin receptor.

It is plausible though, even when conducting studies in animals. When looking at voles, a type of rodent, Dr. Thomas R. Insel found vasopressin acted differently in different species.

While the species are both related, montane voles tend to be more sexually promiscuous, and prairie voles are more of the monogamous type.

This means montane voles are likely to leave your place before breakfast while the prairie vole try to put a ring on it.

When looking at the way vasopressin responded in each of these species, Dr. Insel found vasopressin receptors lit up in completely different areas of the brain, which in turn, caused vastly different effects on behavior.

For prairie voles, their vasopressin receptors live close to the reward center of the brain, yet the montane voles' receptors are located in the amygdala, which is linked to the ability to process anxiety and fear.

So, what does this mean for women? It may mean women have a higher likelihood to cheat if they possess these mutated vasopressin genes, but we know this cannot be the sole cause.

For one, we know there are tons of reasons that contribute to infidelity, many of which haven’t even been scientifically measured.

The study does emphasize the power hormones have on our behaviors, which often are misunderstood and underestimated.

Granted, I am by no means advocating everyone go out and attempt to get their genes tested, but I do believe it’s important that men and women actively seek to find more about their hormones and how they affect our choices and responses in relationships.

At the end of the day, this study will never negate the different reasons men and women engage in infidelity, whether it be socially, emotionally or physically.