Many Genes Influence Same-Sex Sexuality, Not a Single ‘Gay Gene’

The researchers also looked at answers to other questions in the 23andMe survey, including people’s sexual identity and what gender they fantasized about. There, they found considerable genetic overlap between those results and whether people ever engaged in same-sex sex, suggesting that these aspects of sexual orientation share common genetics, they said.

Dean Hamer, a former National Institutes of Health scientist who led the first high-profile study identifying a genetic link to being gay in 1993, said he was happy to see such a large research effort.

“Having said that, I’d like to emphasize that it’s not a gay gene study — it’s a study of what makes people have a single same-sex experience or more,” said Dr. Hamer, now an author and filmmaker. The gene he identified was on the X chromosome, one of the sex chromosomes, a location the new study did not flag as being significant for same-sex sexual behavior.

“Of course they didn’t find a gay gene — they weren’t looking for one,” Dr. Hamer said.

Experts widely agree that the research was conducted by first-rate scientists.

“I kind of held my breath when I first saw the study — I thought, oh no,” said Dr. Mills of Oxford. “But it’s the top geneticists and some of the top social scientists in the field working on this, so if somebody was going to do it, I’m glad they did it.”

Indeed, Dr. Neale, who also consults for several pharmaceutical companies, said one reason his team did the study was to ensure less careful researchers would not tackle it first, “given how sensitive and hot-button this topic really is and how personal it is.”

Robbee Wedow, a member of the research team who also belongs to [email protected], served as a kind of bridge, organizing meetings between the researchers and their Broad Institute critics.