Scientists Debunk the Idea There Is a 'Gay Gene' That Determines Same-sex Attraction

A person's genes do not determine whether they will be attracted to members of the opposite sex, scientists believe. The research debunks the idea that there is a so-called "gay gene," say the authors of the study published in the journal Science. They said the findings highlight the complexity of human traits such as sexuality.

Between two to 10 percent of the world's population at any given time report having same-sex partners, according to research cited by the authors. But scientists aren't sure what determines whether a person will identify as gay, straight, bisexual, or somewhere else on the spectrum of sexuality.

The study involved 477,522 participants. Researchers scanned their genomes to uncover whether there are genes associated with same-sex attraction. This approach is known as a genome-wide association study (GWAS).

The participants of the study were part of the UK Biobank cohort and consenting customers of 23andMe, a genetic testing service.

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A stock image of a man flying a rainbow flag, the symbol of LGBTQIA peoples. Getty

The team found five loci—or the position of a gene on a chromosome—associated with same-sex attraction. The loci had small individual effects, spread across the genome, which partly overlapped in females and males, they explained. But the team said these couldn't meaningfully predict a person's sexual behavior.

"There is certainly no single genetic determinant (sometimes referred to as the "gay gene" in the media)," they wrote. "Our findings provide insights into the genetics underlying same-sex sexual behavior and underscore the complexity of sexuality."

It appears that, like most behavioral traits, sexuality is influenced by a range of genetic variants which can't be picked up in the sample size, they said.

Appearing to allude to the discrimination which LGBT people face, the authors wrote: "Our findings provide insights into the biological underpinnings of same-sex sexual behavior but also underscore the importance of resisting simplistic conclusions—because the behavioral phenotypes are complex, because our genetic insights are rudimentary, and because there is a long history of misusing genetic results for social purposes."

In an article accompanying the research in Science, Melinda Mills, Professor of Sociology at the University of Oxford, who did not work on the paper wrote: "Although they did find particular genetic loci associated with same-sex behavior, when they combine the effects of these loci together into one comprehensive score, the effects are so small (under 1 percent) that this genetic score could not be reliably used to predict same-sex sexual behavior of an individual."