An extensive new study has dismissed the idea that a single ‘gay gene’ exists.

Researchers examined the genetics of almost half a million people who self-reported whether they had ever had sex with someone of the same sex.

Their findings, published in the Science journal, show that sexuality is influenced by a combination of genetics and environmental factors, comparing it to height, personality and other complex human traits.

The report found there are thousands of genetic variants linked to same-sex sexual behaviour, most with very small effects.

Five genetic markers were “significantly” associated with same-sex behaviour, but even those are not enough to predict a person’s sexuality – together, they accounted for under 1% of same-sex behaviour.

“Genetics is less than half of this story for sexual behaviour, but it’s still a very important contributing factor,” explained Benjamin Neale, an associate professor at Harvard Medical School who worked on the study.

“There is no single gay gene, and a genetic test for if you’re going to have a same-sex relationship is not going to work. It’s effectively impossible to predict an individual’s sexual behaviour from their genome.”

The study has been welcomed by LGBTQ rights groups, including GLAAD who said the new research “provides even more evidence” that being gay, lesbian or bisexual is a natural part of human life.

“This new research re-confirms the long established understanding that there is no conclusive degree to which nature or nurture influence how a gay or lesbian person behaves,” said Zeke Stokes, chief programs officer.

A website set up by researchers explains that the study “provides further evidence that diverse sexual behaviour is a natural part of overall human variation” and should not be used to “disparage” LGBTQ people.