Sexuality is complex. And a new study just came out backing that. Published Thursday in the journal Science, it found that human sexual preferences aren’t influenced by a so-called “gay gene,” but rather a multifaceted mix of various genes, environmental factors, and life experiences. Genetics play a part — but biology is only one piece of the puzzle when determining if someone will have sex with someone of the same sex.
A team of scientists from the U.S., Sweden, Denmark, and the UK looked into the gentic makeup of almost half a million people as part of the largest to ever analyze human sexuality using genetics, The New York Times reported. They noted specifically that they studied “same sex sexual behvior,” and not specifically same-sex attraction or orientation. This sounds like semantics, but those matter in science
“I hope that the science can be used to educate people a little bit more about how natural and normal same-sex behavior is,” one of the study’s lead researchers, Benjamin Neale, a geneticist at the Broad Institute of M.I.T. and Harvard told the New York Times. “It’s written into our genes and it’s part of our environment. This is part of our species and it’s part of who we are.”
Even before it was published, the study was controversial. Some LGBTQ+ scientists said they were worried that the results could “give ammunition to people who seek to use science to bolster biases and discrimination against gay people,” the Times reported. One worry, for example, was that people in power with anti-LGBTQ+ sentiments would call for gene editing, even if it were scientifically impossible.
“I deeply disagree about publishing this,” Steven Reilly, a geneticist and postdoctoral researcher who is on the steering committee of the Broad Institute’s L.G.B.T.Q. affinity group, said, according to the Times. “It seems like something that could easily be misconstrued… In a world without any discrimination, understanding human behavior is a noble goal, but we don’t live in that world.”
But not everyone agrees: An official with GLAAD told the Times: “Anyone who’s LGBTQ+ knows that their identity is complicated and to have science sort of bear that out is a positive thing.”
With that said, scientists consulted with LGBTQ+ advocacy groups before they published their research. This also helped them emphasize some their work’s limitations For example, it only covered self-reported sexual behaviors, so people who weren’t comfortable sharing their sexual history weren’t included. Another caveat: Just because people have hooked up with someone of the same sex, it doesn’t mean they identify as gay or a lesbian, so the researchers didn’t use those terms in their work. They also only included people whose sex as assigned at birth matched their self-reported gender. Therefore, the study excludes non-binary and transgender people, Gizmodo reports. The data is also specifically taken from people with European ancestry, so a large portion of the population wasn’t analyzed.
But all that doesn’t mean the findings aren’t interesting. The study — which was funded by the National Institutes of Health and other agencies — found that sexual behavior is polygenic, which means that hundreds, maybe thousands, of different genes contribute in little ways to it. They also found some notable genetic contrasts in the men and women they studied. Their results also show that there’s not genetic evidence that “the more someone is attracted to the same sex, the less they are attracted to the opposite sex,” the authors said, according to Gizmodo.
Ultimately, they found five different genetic markers that were associated with same-sex sexual behaviors, but none of them had an impact large enough to predict whether someone would report same-sex behvior someday. One such marker: In men, the study made a connection between sexual orientation and chances of baldness. This could mean sex hormones are involved in both traits. Another marker researchers said was relevat was sense of smell. It’s hard to say what that means, but it gives scientists something to build on.
Neale told the Times he hopes the results will show the world that: “diversity is a natural part of our experience and it’s a natural part of what we see in the genetics. I find that to actually just be beautiful.”