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

Ekklesia Millennium Society benefits from second vehicle donation

Spring Honda donated a van, while Minute Muffler ensured it was fit for the road

BC Wildfire Service onsite at small fire west of Kimberley

The BC Wildfire Service is responding to a 0.5 hectare, suspected lightning-caused… Continue reading

Quilt of Valour presented to Kimberley veteran Tim Park

Military Ames coordinator Cindy Postnikoff is also doing the good work of… Continue reading

Lightning blamed for multiple fire starts across Kootenays

Southeast Fire Centre says ground crews, air support responding to fires near Revelstoke, Nakusp

Residents using millions of litres of water during heat wave: City

Millions of litres of water were delivered to residents and businesses on… Continue reading

VIDEO: Otter pups learn to swim at B.C. wildlife rescue facility

Watch Critter Care’s Nathan Wagstaffe help seven young otters go for their first dip

Michael Buble among 13 British Columbians to receive Order of B.C.

Ceremony will be delayed to 2021 due to COVID-19

U.S. border communities feel loss of Canadian tourists, shoppers and friends

Restrictions on non-essential travel across the Canada-U.S. border have been in place since March 2`

Rollout of COVID-19 Alert app faces criticism over accessibility

App requires users to have Apple or Android phones made in the last five years, and a relatively new operating system

Alleged impaired driver sparks small wildfire near Lytton after crash: B.C. RCMP

Good Samaritans prevented the blaze from getting out of control

B.C. First Nation adopts ‘digital twinning’ software to better manage territory

Software allows users to visualize what a mountain might look like if the trees on its slopes were logged

All inquiry recommendations implemented after fatal Port Hardy RCMP shooting: Ministry

The Independent Investigations Office of B.C. cleared the RCMP officers involved of wrongdoing

Most Read