THE SCIENCE BEHIND HOMOSEXUALITY

           

Few parts of human nature are as complicated — or as political — as sexual orientation. A strong genetic relationship suggests that LGBT individuals are "born this way," rather than choosing a lifestyle. However, others fear that such a result may be exploited to "cure" homosexuality, therefore most study teams have avoided the subject.

A new study claims to disprove the theory that same-sex behavior is caused by a single gene or a group of genes. The study, which looked at almost half a million men and women's genomes, discovered that while genetics have a role in who individuals choose to have sex with, there are no precise genetic indicators. However, several scientists doubt that the study, which focused on genes linked to sexual behavior rather than attraction, can make any meaningful conclusions regarding sexual orientation. A team lead by Brendan Zietsch of the University of Queensland in Australia searched multiple large genetic data banks, including 23andMe and the UK Biobank, for the new study (23andMe did not fund the research). They questioned almost 477,000 people if they'd ever had intercourse with someone of the same sex, as well as questions regarding sexual desires and how homosexual or straight they thought they were. The scientists discovered five single spots in the DNA that appeared to be shared by persons who had at least one same-sex experience. Two of these genetic markers are located near genes associated with sex hormones and scent, two characteristics that may influence sexual desire. However, when considered collectively, these five variables explained less than 1% of the variance in sexual activity among the participants in the research. When the researchers looked at the total genetic similarities of people who had a same-sex experience, they discovered that genetics accounted for between 8 and 25% of the behavior. The rest was most likely caused by environmental or biological factors.

Despite the findings, the scientists claim that genetic similarities alone cannot determine whether or not a person is gay. "It's the end of the 'gay gene,'" says Eric Vilain, a geneticist at Children's National Health System in Washington, D.C. who was not involved in the research. However, the study will not be the final word on the perplexing topic of what causes homosexuality. Dean Hamer of the National Cancer Institute in the United States and his colleagues presented a report in 1993 claiming that a region on the X chromosome termed Xq28 may contain a "gay gene." However, other research, including the current work, have revealed no such association, and Sathirapongsasuti believes the latest study is the final nail in the coffin for Xq28 as a source of same-sex desire. Rice and Vilain both agree that the result is ambiguous. A more comprehensive questionnaire that examines more elements of sexuality and environmental effects would help the researchers to better pinpoint the sources of attraction. The authors claim to have discovered correlations between sexual orientation and sexual behavior, although they admit that the genetic linkages do not predict orientation. "I believe we are catching some of that risk-taking behavior," Sathirapongsasuti adds, but the genetic correlations still show that same-sex activity is tied to attraction.

Written by:- Parth Vaza