New genetic links to same-sex sexuality found in huge U.S. study

Genome-wide research on DNA from nearly half a million U.S., U.K. adults found five genetic variants

The largest study of its kind found new evidence that genes contribute to same-sex sexual behaviour, but it echoes research that says there are no specific genes that make people gay.

The genome-wide research on DNA from nearly half a million U.S. and U.K. adults identified five genetic variants not previously linked with gay or lesbian sexuality. The variants were more common in people who reported ever having had a same-sex sexual partner. That includes people whose partners were exclusively of the same sex and those who mostly reported heterosexual behaviour.

The researchers said thousands more genetic variants likely are involved and interact with factors that aren’t inherited, but that none of them cause the behaviour nor can predict whether someone will be gay.

The research “provides the clearest glimpse yet into the genetic underpinnings of same-sex sexual behaviour,” said co-author Benjamin Neale, a psychiatric geneticist at the Broad Institute in Cambridge, Massachusetts.

“We also found that it’s effectively impossible to predict an individual’s sexual behaviour from their genome. Genetics is less than half of this story for sexual behaviour but it’s still a very important contributing factor,” Neale said.

The study was released Thursday by the journal Science. Results are based on genetic testing and survey responses.

Some of the genetic variants found were present in both men and women. Two in men were located near genes involved in male-pattern baldness and sense of smell, raising intriguing questions about how regulation of sex hormones and smell may influence same-sex behaviour.

Importantly, most participants were asked about frequency of same-sex sexual behaviour but not if they self-identified as gay or lesbian. Fewer than 5% of U.K. participants and about 19% of U.S. participants reported ever having a same-sex sexual experience.

The researchers acknowledged that limitation and emphasized that the study’s focus was on behaviour, not sexual identity or orientation. They also note that the study only involved people of European ancestry and can’t answer whether similar results would be found in other groups.

PHOTOS: 50 years of LGBTQ pride showcased in protests, parades

Origins of same-sex behaviour are uncertain. Some of the strongest evidence of a genetic link comes from studies in identical twins. Many scientists believe that social, cultural, family and other biological factors are also involved, while some religious groups and skeptics consider it a choice or behaviour that can be changed.

A Science commentary notes that the five identified variants had such a weak effect on behaviour that using the results “for prediction, intervention or a supposed ‘cure’ is wholly and unreservedly impossible.”

“Future work should investigate how genetic predispositions are altered by environmental factors,” University of Oxford sociologist Melinda Mills said in the commentary.

Other experts not involved in the study had varied reactions.

Dr. Kenneth Kendler a specialist in psychiatric genetics at Virginia Commonwealth University, called it “a very important paper that advances the study of the genetics of human sexual preference substantially. The results are broadly consistent with those obtained from the earlier technologies of twin and family studies suggesting that sexual orientation runs in families and is moderately heritable.”

Former National Institutes of Health geneticist Dean Hamer said the study confirms “that sexuality is complex and there are a lot of genes involved,” but it isn’t really about gay people. “Having just a single same sex experience is completely different than actually being gay or lesbian,” Hamer said. His research in the 1990s linked a marker on the X chromosome with male homosexuality. Some subsequent studies had similar results but the new one found no such link.

Doug Vanderlaan, a University of Toronto psychologist who studies sexual orientation, said the absence of information on sexual orientation is a drawback and makes it unclear what the identified genetic links might signify. They “might be links to other traits, like openness to experience,” Vanderlaan said.

The study was a collaboration among scientists including psychologists, sociologists and statisticians from the United States, United Kingdom, Europe and Australia. They did entire human genome scanning, using blood samples from the U.K. Biobank and saliva samples from customers of the U.S.-based ancestry and biotech company 23andMe who had agreed to participate in research.

Lindsey Tanner, The Associated Press

Like us on Facebook and follow us on Twitter.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Tough year ahead for the aluminium industry

U.S. market is still Canada’s most important

Kitselas receive $1.2M boost for apprenticeship development program, open to Tsimshian and Haisla Nations

Melanie Mark, Minister of Advanced Education announces $7.5M for six Indigenous training programs

PHOTOS: Heavy snowfall breaks window, causing avalanche into Northern Sentinel office

It was a chaotic start to the week for the Kitimat Northern Sentinel

B.C. premier talks forestry, service needs with handful of northern mayors in Prince George

Prince George meeting completes premier’s tour of Kitimat, Terrace, Fort St. James and Quesnel

Indigenous LNG supporters chide human rights advocates over pipeline comments

Coastal GasLink has signed agreements with 20 elected First Nation councils along the pipeline’s 670-kilometre path

Officials reaching out to those in contact with Canada’s first coronavirus patient

The illness has sickened at least 1,975 people and killed 56 in China

Canada’s basketball community mourns Kobe Bryant after helicopter crash

Bryant was an 18-time NBA all-star who won five championships

‘Devastated’: Fans, celebrities remember Kobe Bryant after his death

Bryant played all of his 20-year career with the NBA with the Los Angeles Lakers

Kobe Bryant, daughter killed in California helicopter crash

Bryant entered the NBA draft straight out of high school in 1996

Investigation launched after six dead puppies dumped in Richmond hotel parking lot

RAPS reminds people they can always give up puppies they can’t take care of

Canadian Lunar New Year celebrations dampened by coronavirus worries

But Health Minister Patty Hajdu said today that the risk of infection is low

B.C. VIEWS: New coronavirus outbreak an important reminder

Walking the line between cautious and alarmist

Risk of coronavirus low in B.C. as first case emerges in Toronto: officials

There have been no confirmed cases of the virus in B.C.

Most Read