Decades ago, before the Human Genome project, there was speculation there might be a gay gene. While some applauded the idea - sexuality wasn't a choice - others were concerned that future science might start switching such genes off.

Neither extreme turned out to be valid and a new study affirms what scientists have long said; there is no "gay" gene. The genome-wide association in Science used 477,522 people, 26,827 reported same-sex sexual behavior. Even when all tested genetic variants were taken into account, they collectively accounted for no more than a quarter of the same-sex behavior reported by the study participants. 

They found two spots in the genome that were correlated to same-sex behavior in both sexes plus two just in men and one in women but the five locations could account for much less than 1% of same-sex sexual behavior on a population level.


DOI: 10.1126/science.aat7693

"Same-sex sexual behavior is influenced by not one or a few genes but many. Overlap with genetic influences on other traits provides insights into the underlying biology of same-sex sexual behavior, and analysis of different aspects of sexual preference underscore its complexity and call into question the validity of bipolar continuum measures such as the Kinsey scale," the authors write.

“The findings themselves reinforce this idea that diversity of sexual behavior across humanity is really a natural part of our overall diversity as a species,” Benjamin Neale, a geneticist at the Broad Institute of MIT and Harvard and one of the study’s senior authors, told the LA Times. “That’s a really meaningful and important result.”