“That which does not kill us makes us stronger.” ― Friedrich Nietzsche

Is there a “cheating gene”? Well, it’s complicated. Anecdotal evidence suggests that 2/3 of women whose mother was unfaithful are unfaithful themselves. This evidence also suggests that 1/2 of men are unfaithful if their father was unfaithful too. But is that nature or nurture? Human sexual choices and behaviors are directed by a number of factors including our relationship with our parents, societal influences and interactions and yes, our genetics. Let’s take a deeper look at how our genetics might play a role.

Cheating: Hormones and Genetics

To understand how genetics might play a role in infidelity, it’s first necessary to understand three important hormones: vasopressin, oxytocin and dopamine. In the animal kingdom, some animals pair bond and mate for life while others do not. One of the differences between the two are the number of receptors and sensitivity to two of the hormones mentioned–vasopressin and oxytocin. The more receptors for these two hormones and the greater the sensitivity to them, the more likely that animal species is to mate for life.

In humans, the number of receptors for vasopressin and oxytocin as well as our sensitivity to them is determined by our genetics. The number and type of receptors for the third hormone, dopamine, is also determined by our genetics but it works differently. People with a weaker type of dopamine receptor (called a D4 receptor) tend to engage in riskier behaviors than the average population in order to experience a rush of dopamine. Because of their fewer receptors or weaker receptor types, it takes riskier behavior such as gambling, drug and alcohol abuse or infidelity to give these individuals the same experience of dopamine that another person might get from a bite of chocolate.

Twin Study on the Cheating Gene

In 2014, a twin study analyzed 7,400 twins including both identical twins (sharing identical genomes) and fraternal twins (unique genomes). The study found that the identical twins reported the same level of infidelity whereas the fraternal twins did not. The author of that study concluded that our genetics influence cheating behavior in as many as 63% of men and 40% of women.

Now, before you give a cheater a pass due to genetics, keep in mind that we are not slaves to our biology. While the genetic influence on the number and sensitivity of various hormone receptors does exist, so too does personal responsibility. We have the ability of reason and can make decisions about fidelity regardless of our genetic predispositions. So, is there a “cheating gene”? It’s impossible to say there isn’t some genetic influence on fidelity but our ability to reason and think independently means we are not ruled by our genetics. If you suspect your partner is cheating, Bulldog PI can help you find the truth you deserve.