New Study Seen to Support 'Born Gay' Theory
(CNSNews.com) - A new study on homosexuality is being used to back up the contention that sexual orientation is determined in the womb and not by sociological factors.
North American researchers say a study of almost 1,000 Canadian men found a link between homosexuality and the number of older brothers a man has. Such an association has been reported before, but in the past left open the possibility that both biological or sociological factors may play a role.
This time, however, the researchers say the link appears to exist irrespective of whether the man was brought up with the brothers.
It was not, therefore, the result of environmental factors in place while the man was growing up, but rather linked to whether the man's mother had previously given birth to boys - a purely biological factor.
Of the participants in the study, roughly one-third were deemed "heterosexual" - the researchers determined this from their responses to questions about sexual attraction and sexual behavior - a little under half were "homosexual," and the rest were "bisexual."
For every male baby the mother had carried in the womb before the subject was born, the chances of the subject growing up homosexual increased by about one-third, said the researchers. They stressed that the starting point was very low, and that even with older brothers, the chances of men being heterosexual was 95 percent.
The study, published in the Proceedings of the National Academy of Sciences, is being reported widely around the world, under such headlines as "Gay men may be born, not made," "Being gay starts in the womb" and "Sexual orientation of men determined before birth."
One British report declared that the study "provides the strongest evidence yet of a biological basis for male homosexuality."
The research was carried out by a team led by psychologist Anthony Bogaert at Canada's Brock University, who said the homosexuality-older brother effect was not affected by social or psychological factors like family structure, styles of child-rearing or education.
The link was also not found in cases where there were younger brothers, sisters of any age, older step-brothers, or older adopted male siblings.
"Only biological older brothers, and not any other sibling characteristic, including nonbiological older brothers, predicted men's sexual orientation, regardless of the amount of time reared with these siblings," Bogaert said.
"These results provide evidence that a prenatal mechanism, and not social and/or rearing factors, affects men's sexual orientation development."
One possible explanation, he said, was that the mother's immune system builds up antibodies in response to carrying male babies, thus affecting the developing brain of a later male baby and having a bearing on his sexuality.
Many conservatives dispute the notion that homosexuality is an orientation that is hardwired in a child's genes before birth.
In a 1995 publication on the research on homosexuality and biology, the U.S. group Parents, Families and Friends of Lesbians and Gays (PFLAG) stated: "No human behavior, let alone sexual behavior, has been connected to genetic markers to date ... sexuality, like every other behavior, is undoubtedly influenced by both biological and societal factors."
An organization of mental-health professionals called the National Association for Research and Therapy of Homosexuality (NARTH) is promoting a petition urging the American Psychological Association (APA) to support a person's right either to "claim a homosexual identity or to pursue change in sexual adaptation."
The APA contends that sexual orientation is shaped by interactions of "biological, psychological and social factors."
NARTH agrees with that, but says it places more emphasis on the psychological influences, while the APA stresses biological influences.
NARTH also says there is no such thing as a "gay gene," although it says genetic factors may play a role in some people.
"But none of these factors mean that homosexuality is normal and a part of human design, or that it is inevitable in such people, or that it is unchangeable."