US researchers find evidence that homosexuality linked to genetics

Compared to straight men, gay men are more likely to be left-handed, to be the younger siblings of older brothers, and to have hair that whorls in a counterclockwise direction.

US researchers are finding common biological traits among gay men, feeding a growing consensus that sexual orientation is an inborn combination of genetic and environmental factors that largely decide a person’s sexual attractions before they are born.

Such findings – including a highly anticipated study this winter – would further inform the debate over whether homosexuality is innate or a choice, an undercurrent of California’s recent Proposition 8 campaign in which television commercials warned that “schools would begin teaching second-graders that boys could marry boys”, suggesting homosexuality would then spread.

Some scientists say the political and moral debate over same-sex marriage frequently strayed from established scientific evidence, including comments by Republican vice-presidential candidate Sarah Palin that homosexuality is “a choice” and “a decision”.

Until 2007, CNN polls had found that a majority of Americans believed gay people could change their sexual orientation if they chose to; it was only last year that a majority for the first time said homosexuality was an inborn trait.

Christian groups such as Exodus International argue “that homosexuals who desire to change can do so”. One prominent psychiatrist, Dr Robert Spitzer of Columbia University, found controversial evidence that therapy can cause some gay people to change to a heterosexual orientation, although the study concluded that a “complete change” was uncommon.

While sexual behaviour may be chosen, the preponderance of researchers say attraction is dictated by biology, with no demonstrated contribution from social factors such as parenting or other factors after birth.

 US researchers find evidence that homosexuality linked to genetics
guardian.co.uk, UK -