Genes linked to homosexuality are also present in some straight people, where they cause different sexual behaviors, study says

Genes linked to same-sex sexual behaviour are also found in straight people — where they are associated with having more sexual partners, a study has found.

Such a mating advantage could outweigh the 'loss' of reproduction among gay individuals and explain the persistence of these genes throughout human evolution.

This is the conclusion of researchers led from the University of Queensland, who studied the genomes of 477,522 people from both the UK and the US.

However, they cautioned, further research will be needed to confirm the findings, given the small size of the genetic differences studied and the limited sample range.

The research was undertaken by psychologist Brendan Zietsch of the University of Queensland, Australia, and his colleagues.

'Human same-sex sexual behaviour is heritable, confers no immediately obvious direct reproductive or survival benefit and can divert mating effort from reproductive opportunities,' the researchers wrote in their paper.

'This presents a Darwinian paradox: why has same-sex sexual behaviour been maintained despite apparent selection against it?'

In their study, the team analysed the genomes of a total of 477,522 individuals from the UK and US, comparing those who had engaged in same-sex sexual behaviour with those who exclusively had sex with members of the opposite sex.