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Researchers link promiscuity to genetics

Those who choose promiscuity over monogamy often have their fair share of excuses.

The results of a Binghamton University research study suggest that a new item may belong on their lists: genetics.

BU researchers have come up with a theory that links sexual promiscuity and infidelity to variations in a gene, meaning the reason some people have uncommitted sex and cheat while others stay monogamous may come down to biology.

Variations in the D4 polymorphism, or DRD4 gene, could be one of the determining factors in a person’s sexual behavior, according to Justin Garcia, a SUNY doctoral diversity fellow in the laboratory of evolutionary anthropology and health at BU who led the team of researchers.

The DRD4 gene has been linked, through previous studies, to feel-good, sensation-seeking behavior such as the use of alcohol, illegal drugs and gambling. This is because variations in the gene influence how readily the body accepts dopamine.

When dopamine is released in the body, it causes pleasure, which is where the sexual promiscuity issue comes into play.

“Dopamine is a neurotransmitter that is believed to have numerous effects, such as an influence on reward-seeking behavior and addiction,” said Anthony Fiumera, assistant professor of biological sciences at BU. “So it is not surprising that it may impact mating choices in humans.”

According to Garcia, who teaches Human Sexuality and a seminar titled “Bioculture of Love” at BU, the motivation for uncommitted sex stems from a system of pleasure and reward — the reward being the dopamine.

“In cases of uncommitted sex, the risks are high, the rewards substantial and the motivation variable — all elements that ensure a dopamine rush,” Garcia said.

In his study, Garcia and his team collected a detailed history of the sexual behavior and relationships of 181 BU undergraduate students. This, along with samples of their DNA, allowed them to determine that variations of the gene in question can influence behavior.

“What we found was that individuals with a certain variant of the DRD4 gene were more likely to have a history of uncommitted sex, including one-night stands and acts of infidelity,” Garcia said.

The results of the study showed that students with the genetic variation were twice as likely as those without it to engage in sexually promiscuous behavior. In addition, 50 percent of those with the gene variation had been unfaithful in a relationship, while only 22 percent of those without the variation had.

But the results may indicate something of a contradiction. Because the DRD4 variation and desire for a dopamine rush can function independently from the desire for a committed relationship, the data suggests that someone can deeply care for their partner and still be unfaithful.

Even so, both Fiumera and Garcia cautioned against using genetics as an excuse for the behavior.

“The study doesn’t let transgressors off the hook,” Garcia said. “These relationships are associative, which means that not everyone with this genotype will have one-night stands or commit infidelity. Indeed, many people without this genotype still have one-night stands and commit infidelity. The study merely suggests that a much higher proportion of those with this genetic type are likely to engage in these behaviors.”

Fiumera echoed this statement.

“I don’t think my wife, also a geneticist here at Binghamton, would accept ‘my genes made me do it’ as an excuse,” he said.

Using the results, Garcia and his team of researchers plan to further explore the significance of their findings through a series of follow-ups and related studies.

“First, we plan to replicate this study on a larger sample and look at several other genetic markers,” Garcia said. “We will continue our work on hookup behavior, infidelity and romantic love.”