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New study supports

Tue 4 Jul 2006 In: International News

A new study has shown that the more older brothers a male has, the more likely he is to be gay – the first such study to link sexuality solely with biological factors, excluding environmental or cultural determinants. The study of 1000 Canadian gay, bisexual and straight men showed that having biologically related older brothers – not adopted older brothers – and irrespective of whether the man was brought up with his brothers, increased the likelihood that he was gay. Thus, researchers concluded that being gay was related solely to the number of boys his mother had previously given birth to – a purely biological factor. For every male baby the mother had carried prior to giving birth to the subject, his chances of being gay were increased by around one-third. Researchers stressed that the starting point was very low, however, and even with older brothers the chance of being heterosexual was still 95 per cent. “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,” said researcher and psychologist Anthony Bogaert of Canada's Brock University. “These results provide evidence that a prenatal mechanism, and not social and/or rearing factors, affects men's sexual orientation development.” A possible explanation, say researchers, is that the mother's immune system builds up antibodies in response to carrying male children, thus affecting the developing brain of a later male child, predisposing him to being gay. In spite of this latest research, the conservative National Association for the Research and Therapy of Homosexuality (NARTH) is petitioning the American Psychological Association (APA) to emphasise psychological influences in determining sexuality, and to downplay any biological or genetic influence. The APA says sexual orientation is shaped by interactions of “biological, psychological and social factors.” NARTH says there is no such thing as a gay gene. Besides, “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.”    

Credit: News Staff

First published: Tuesday, 4th July 2006 - 12:00pm

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