There is no ‘gay gene’ to predict sexuality
The largest-ever study into the link between sexuality and genetics has found that there is no “gay gene” that determines a person’s sexual orientation. Instead, same-sex attraction appears to be driven by a complex mix of genetic, cultural, and environmental influences—just like many other human traits. “It’s effectively impossible to predict an individual’s sexual behavior from their genome,” coauthor Ben Neale, from the Broad Institute of MIT and Harvard, tells CBSNews.com. Homosexuality and bisexuality are a “normal part of variation in our species.” The researchers examined the genetic profiles of nearly 480,000 people in the U.K. and U.S.—about 100 times more than any previous study into genetics and same-sex attraction—who were also asked whether they had ever had a samesex partner. The scientists identified five specific genetic variants associated with same-sex behavior, including one linked to the biological pathway for smell and others connected to the regulation of sex hormones. Overall, genetics accounts for 8 to 25 percent of same-sex behavior, when thousands of tiny variations across the whole genome are taken into account, researchers concluded. Sexual orientation “is influenced by genes but not determined by genes,” said researcher Brendan Zietsch. But genetic variation does appear to have a stronger influence on same-sex behavior in men than in women, suggesting that female sexuality is more complex.