This comes out of a recent study of 7,378 Finnish people between the ages of 18 and 49, where researcher addressed the question if cheating may run in families and if infidelity in fact is genetic? The research in fact uncovered a genetic component to bed-hopping by identifying a link between specific mutations of a receptor gene for vasopressin and infidelity in women…but not men.
Vasopressin is a hormone that is synthesized in the hypothalamus and stored in the posterior pituitary. From there, the hormone is secreted into the bloodstream; however, some of the hormone may release directly into the brain. Recent research suggests vasopressin impacts our trust and empathy levels, playing an important role in bonding, social behavior, and sexual motivation.
Interestingly, Vasopressin has a very brief half-life: just 16 to 24 minutes. Mutations in a receptor gene might alter its function and so affect behavior normally modulated by its matching hormone. To test this theory, the research team data from an extensive study of Finnish twins and their siblings, winnowing the field of participants down to a subset of 7,378 people who had been in a relationship during (at least) the last year. Of these people, 9.8 percent of the men and 6.4 percent of the women reported having had two or more sexual partners over the previous year. After collecting saliva samples and sequencing genomes, the scientists analyzed all the data.
A significant relationship was found between five separate variants of the vasopressin receptor 1A gene (AVPR1A) and infidelity in women. Very strangely, the same link did not exist for men; and nothing connected the oxytocin receptor gene (OXTR) to the sexual behavior of either sex. This may be interesting too, since as the companion to vasopressin, oxytocin, the so-called love hormone, is released whenever we hug or kiss another person, while giving birth or breastfeeding, and during sex.
Because the study involved twins and siblings, the researchers also analyzed the impact of genetic and environmental factors. Brother-sister sibling pairs were not found to be similarly unfaithful. Genes, the researchers concluded, accounted for about 63 percent of the variation in faithless behavior in men and 40 percent in women. Significant genetic influences accounting for around half the variation in extrapair mating in both sexes were found, confirming biological underpinnings to the behaviour.
Despite causing pulses to race, research on the genetic underpinning cheating is incomplete and not yet fully conclusive. As with genetic backgrounds, there are confounding factors, that may heavily influence the resulting phenotype, i.e., marital infidelity. Such factors may include money, unhappiness, depression, abusive behaviour, to name just a few.