There’s no such thing as a “gay gene.”
No single element of a person’s genome that dictates whether he or she will prefer same-gender sex, concludes a major new study of the long- and fiercely-debated question.
But, researchers say, parts of an individual’s larger genetic makeup can correlate with same-sex behavior.
The study, which scrutinized genetic and behavioral data from nearly half a million people of both sexes in Britain, the United States and Sweden, was published Thursday in the journal Science.
The study “is not the first to explore the link between genetics and same-sex behavior, but it is the largest of its kind, and experts say it provides one of the clearest pictures of genes and sexuality,” reports the Washington Post.
The researchers “found that it’s effectively impossible to predict an individual’s sexual behavior from their genome,” psychiatric geneticist Benjamin Neale of the Broad Institute in Cambridge MA told the Associated Press. “Genetics is less than half of this story for sexual behavior but it’s still a very important contributing factor.”
The study is not without its critics.
“Several scientists who are part of the L.G.B.T.Q. community … said they were worried the findings could give ammunition to people who seek to use science to bolster biases and discrimination against gay people,” says the New York Times.
“One concern is that evidence that genes influence same-sex behavior could cause anti-gay activists to call for gene editing or embryo selection, even if that would be technically impossible,” the Times says. “Another fear is that evidence that genes play only a partial role could embolden people who insist being gay is a choice and who advocate tactics like conversion therapy.”
The researchers located five “genetic variants that were statistically associated” with same-sex behavior, says the Post. “One of the variants was found in a stretch of DNA that includes several genes related to the sense of smell,” while another, which sits near genes linked to male sex determination, relates to male pattern baldness.
But there are “thousands” of other variants that crop up in the human genome that smaller effects — some “correlated with same-sex sexual behavior in men, others in women, and some in both,” the Post says.
In total, the study concludes, all genetic factors account for slightly less than a third (32%) of same-sex behavior.
Eric Vilain, director of the Center for Genetic Medicine Research at Children’s National Health System, told the Post the findings put an end to the “simplistic concept” of a “gay gene” — while at the same time they capture “the complexity of same-sex attraction.”
Nevertheless, there are limitations to the study’s conclusions, Vilain said, the most obvious being its lack of diversity, since virtually all of the participants were Europeans or Americans of European ancestry.
“It’s missing out on what’s going on in other populations,” he said.
Despite the limitations, this research is much larger and more varied than previous studies, which generally focused on gay men, often those who were twins or were otherwise related.
“Just the fact that they look at women is hooray,” said Melinda Mills, a professor of sociology at the University of Oxford, who wrote a commentary that Science published alongside the study.
