Is Infidelity Genetic?
Study Suggests Brain Chemistry Plays a Role in People’s Ability to Commit
By Katrina Woznicki
WebMD Health News
Reviewed by Laura J. Martin, MD

Dec. 2, 2010 -- Genes associated with sensation-seeking behaviors, such as drinking alcohol or gambling, may also be associated with sexual promiscuity and infidelity, according to a new study.

Researchers led by Justin Garcia, an investigator and SUNY Doctoral Diversity Fellow at the State University of New York in Binghamton, looked at possible biological mechanisms behind the compulsion to be unfaithful to one’s partner or to be sexually promiscuous. They interviewed 181 young adults, asked them about their sexual behavior and relationships, and took samples of their DNA. Seventy-seven percent of the group reported a history of sexual intercourse.

The findings suggest that genetic variation may indeed influence sexual behavior.
Influence of Genetics in the Bedroom

Garcia and his team focused specifically on the DRD4 gene, which is associated with other behaviors linked with reward and feeling good.

People with a genetic variation of DRD4 called 7R+ were more likely to commit infidelity or be promiscuous; 50% of people with 7R+ reported being unfaithful, compared with 22% of people who did not have this genetic variation. Gender did not play a role in genetic variation; 23% of women and 26% of men in the group were found to have the 7R+ genetic variation. The results are published in the Public Library of Science's PLoS ONE journal.

“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 says in a news release. “The motivation seems to stem from a system of pleasure and reward, which is where the release of dopamine comes in. In cases of uncommitted sex, the risks are high, the rewards substantial, and the motivation variable -- all elements that ensure a dopamine ‘rush.’”
More Research Needed

Garcia notes that his findings do not indicate a cause-and-effect association between genetics and sexual behavior, but the study does provide evidence that biology affects human behavior and the decisions people make in their personal lives. He said more research is needed with larger groups of men and women to pinpoint any potential genetic markers that influence sexual behavior.

“These relationships are associative, which means that not everyone with this genotype will have one-night stands or commit infidelity,” Garcia says. “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.”