“I’m serious Jo,” my friend Tony declared as we discussed monogamy, infidelity, and who cheats more—men or women. “Men are genetically made to spread their seed, and to have multiple sex partners. It’s science; it’s how we have evolved and continued as human beings.” This may be, in some ways, true.

We definitely know that our mating rituals, and even our desires to pair off and be monogamous begins in our brains through the release of certain hormones. But I wonder if our propensity to “cheat,” or seek multiple partners even, is a result of natural science or social science? Neuroeconomist and author Paul Zak asserts there are three specific hormones that inspire us to pursue monogamy: oxytocin, arginine vasopressin, and testosterone. Zak contends:

Oxytocin has been shown in animals and humans to sustain pair bonds in males and females through its release in the brain during sex, touch, and nearly any positive social signal… Arginine vasopressin motivates mate- and offspring-guarding in male socially monogamous mammals, an important aspect of pair-bonding. Testosterone is associated with libido and many of the male characteristics like musculature and drive that are attractive to females when seeking high-quality male genes.


Also according to Zak’s research, testosterone (which men have five times more of than women) motivates us to seek out multiple partners. He even comments that “the size of men’s testicles and the shape of their penises evolved [because] females would have multiple sexual partners and it was a ‘let the best sperm win’ all-out competition.”

I find these statements from Zak seemingly contradictory from a lay(wo)man’s standpoint, as it appears that men secrete testosterone in an effort to “get chose” by women who have multiple men to choose from. Also, if men’s sex organs evolved in an effort to mate with women who had “multiple sex partners,” then women have been getting their fair share of (multiple partner) sex as well. Therefore, in my mind, the idea that men are genetically predisposed to cheat, because MAN!, needs more people.

There may be, however, an “infidelity gene” according to some other researchers—particularly a team from State University of New York in Binghamton, who published a study on the gene DRD4 in the scientific journal PLoS ONE (Public Library of Science).

Regarding the study, Christian Nordqvist writes:

181 young adults were interviewed regarding their relationships and sexual behaviors. Samples (buccal wash) were taken for DNA testing. 77% of those interviewed said they had a history of sexual intercourse. The researchers found 50% of those with 7R+—a genetic variation of DRD4—had been unfaithful to their partner, compared to 22% of these without 7R+.

The impact of 7R+ on infidelity and/or promiscuity in males and females appeared to be about the same.

Looking at cheating, or an inability to be monogamous, from a sociological standpoint, we realize many societal factors lead to our views on monogamy and who cheats more. Regardless of whether men or women are more prone to be non-monogamous, cheating comes down to self-control.

According to another study conducted at Texas A&M University, although there’s no difference between the amount of self-control available to men and women, men appear to be more willing to act on their impulses to cheat (or be non-monogamous) than women.

Why? Well we all know the answer to that. If you grew up anything like I did, sexual/relationship/marital infidelity was explained as something men just do. As my friend Tony explained so passionately, we’re taught that men cheat because they can’t help it, because their bodies betray them—even though science cannot fully confirm these facts. We’re also taught that women have less desire to cheat (and less desire for sex overall), as if this is a scientific fact.

The truth is, women are socialized to not cheat while men aren’t, because women suffer greater punishments as a result of infidelity (both socially and otherwise) than men do. One only has to remember The Scarlett Letter, or any real-life woman even accused of having an affair for that matter, as an example. Women who cheat are harlots, whores, bad moms, and untrustworthy employees, friends or future lovers. Men who cheat are only men who cheat.

As women become more financially independent, and norms concerning sex evolve, studies show that cheating wives are catching up to cheating husbands. But I’m not bragging about this new data. Life has taught me that people who are mature and responsible either refrain from committing to a relationship that demands monogamy or practice the self-control necessary to honor their commitments.

Of course, polyamory is an entirely different conversation that we should discuss one day.