A controversial new study now says that homosexuality is not a lifestyle choice but is something that is deeply ingrained in a person’s biology.
The research, conducted by the NorthShore university in Illinois claims to have found genetic markers that can say if a man is gay or not.
Researchers looked at the DNA of over 2,000 people and located two regions of chromosomes that may be linked to a man’s sexuality.
However, the study has been dubbed as being ‘by independent scientists, and the study's authors admit the link is 'speculative'.
They say, however, that the research could help them get closer to finding so-called 'gay genes'.
However, this is not the first time such a study has been conducted. In 1993, American geneticist Dean Hamer found families with several gay males on the mother’s side, suggesting a gene on the X chromosome.
He went on to show that pairs of bothers who were openly gay shared a small region at the tip of the X chromosome and proposed that it contained a gene that predisposes a man to like members of the same sex.
In the latest study researchers at NorthShore University (NSU) HealthSystem’s Research Institute, based in Evanston, made the findings after conducting a genome-wide association study (GWAS).
This examined the sexual orientation of 1,077 homosexual and 1,231 heterosexual men. They found two regions with multiple genetic variants most strongly associated with sexuality.
These were located on chromosomes 13 and 14, near genes that have functions which may be relevant to the development of sexual orientation.
Alan Sanders, a psychiatrist who studies behavioural genetics at NSU who led the study, said that the goal of the study was to search for genetic underpinnings of male sexual orientation, and thus ultimately increase knowledge of biological mechanisms underlying sexual orientation.
However, researchers emphasised that although the top two association regions provide interesting and perhaps trait-relevant examples with their closest genes, the potential connections remain speculative.
Lovell-Badge, group leader at The Francis Crick Institute biomedical research centre in London, however, said that the study was ‘problematic’ and “ traits like being gay that are likely to involve many genes and where "environmental" influences, perhaps both in utero and postnatally, can have a strong effect.” He stressed on the fact that correlation does not mean causation.
Professor Gil McVean, who specialises in statistical genetics at the University of Oxford, added that the researchers have found weak evidence for genetic variation that influences self-reported sexual preferences in men.
The full findings of the study were published today in the Nature journal Scientific Reports.