Homosexuality may be linked to hormonal changes in the brain, predisposing some people to homosexual preferences, according to Roger Gorski, director of the neuroendocrinology lab at UCLA's Brain Research Institute.
"My opinion is that being gay is not a matter of choice," he said.Gorski spoke recently as part of the Family Fellowship Parents Conference. The group was organized to strengthen Mormon families with homosexual members.
Gorski argues that hormonal changes in fetuses account for minute differences in the brain that dictate sexual attraction and possibly even behavior.
But research on possible causes of homosexuality is still in its infancy, said David Pruden, executive director of Evergreen International, an organization that counsels gays and lesbians to help rid themselves of homosexual urges. What's more, scientists have been unable to duplicate the results of the handful of studies that have been done.
"There are so many factors that affect this issue that no one has been able to come up with a conclusive biological argument - and no one has been able to come up with a conclusive psychological argument," he said.
Pruden pointed to a recent Columbia University paper collecting the studies that have been done thus far on sexual orientation. It concluded that there is no basis to assert biological causes of sexual orientation at this point.
Most of Gorski's experimentation has been conducted on rats, whose sexual orientation is determined by hormones after birth. Before that time the brain is female and will develop as such, barring a hormonal influence.
Gorski concentrated his research on rats because of their late sexual determination. Human research has been very limited, Gorski said, because there is no way to give the hormone dose in utero and there are clear ethical problems with doing so.
"The nature-nurture argument is passe," Gorski said. "There is no question nature and nurture play a part in sexual identification."
Nevertheless, Gorski acknowledged that his research on rats can be applied to humans only to a limited extent. Sexual attraction in humans is more complex than in rats, which are attracted solely by hormones, and sexual hormonal influence in humans takes place before birth rather than after.
"I believe there are sex differences in the human brain. I believe they are influenced by hormones. As a scientist, I have to stop there," he said.