According to the study's principal author and group leader for the European Molecular Biology Laboratory at the Institute of Molecular Medicine in Finland, Andrea Ganna, same-sex sexual behaviour is just "a natural part of our diversity as a species."
For LGBTQ advocates, that word "natural" cannot be overstressed. "Natural" means being gay is not a choice.
But here's the quote that will delight opponents of LGBTQ rights, some of whom insist they can "convert" gay people to choose to be straight by praying the gay away:
"There is no ‘gay gene’ that determines whether someone has same-sex partners,” said Ganna, who is also a geneticist at the Broad Institute of MIT and Harvard as well as the University of Helsinki.
Ganna's research revealed there are a number of genetic variations that can influence sexual behavior.
Even though the paper published today in the Journal Science doesn’t name the ingredients for what exactly causes a human being to deviate from the most common form of sexual orientation: heterosexuality.
As the Washington Post first reported Thursday, the scientists conducted this study by collecting DNA from more than 470,000 people.
“The study is a big step forward because of its huge size,” J. Michael Bailey, a Northwestern University psychologist with experience in genetics, told Science News. Bailey was not a part of this study.
Those hundreds of thousands of participants were found within two huge genetic databases: the home DNA testing company 23andMe, the UK Biobank, as well as from three smaller studies.
Volunteers answered questions about how many sexual partners they have had, and what kinds of sex they had had.
23andMe customers were asked what they found attractive in a sexual partner, about their sexual identity and their sexual fantasies.
The researchers' analysis identified five genes which are clearly connected with same-sex sexual attraction.
While the variations in these genes are not enough to raise a rainbow flag and label anyone as unquestionably gay, the researchers say these biological variants may at the very least partly influence sexual behavior.
One was discovered in a chain of DNA which includes several genes related to the sense of smell; another one of the genes is related to male pattern baldness, which the authors said could suggest that sex hormone regulation may somehow be involved.
“There’s a lot of room for nongenetic effects,” Bailey told Science News. Coauthor Benjamin Neale, a geneticist at Massachusetts General Hospital in Boston and the Broad Institute, agreed.
The study, he said, makes clear both biology and one’s environment may be a factor that influences sexuality. What does he mean by "environmental"?
A range of experiences in a person's development as well as social and cultural factors that all could affect behavior, Neale said.
Whether Bailey's "nongenetic" critique is fair isn't the point, said coauthor J. Fah Sathirapongsasuti, a computational biologist at 23andMe in Mountain View, Calif.
“Just because something is not completely genetic or something has an environmental, or what we call nongenetic, component," said Sathirapongsasut, "doesn’t mean it’s a choice.”
GLAAD's Zeke Stokes went one better.
This new research, he said “provides even more evidence that being gay or lesbian is a natural part of human life, a conclusion that has been drawn by researchers and scientists time and again.
The identities of LGBTQ people are not up for debate. This new research also reconfirms the long established understanding that there is no conclusive degree to which nature or nurture influence how a gay or lesbian person behaves.”