Homosexuality due to womb30th June 2006
A man's sexual orientation may be determined by conditions in the womb, according to a study.
Previous research had revealed the more older brothers a boy has, the more likely he is to be gay, but the reason for this phenomenon was unknown.
But a Canadian study has shown that the effect is most likely down to biological rather than social factors. The research is published in the journal of the Proceedings of the National Academy of Sciences.
Professor Anthony Bogaert from Brock University in Ontario, Canada, studied 944 heterosexual and homosexual men with either "biological" brothers, in this case those who share the same mother, or "non-biological" brothers, that is, adopted, step or half siblings.
He found the link between the number of older brothers and homosexuality only existed when the siblings shared the same mother. The amount of time the individual spent being raised with older brothers did not affect their sexual orientation.
Writing in the journal, Professor Bogaert said the results support a prenatal origin to sexual orientation development in men. He suggests the effect is probably the result of a "maternal memory" in the womb for male births.
A woman's body may see a male foetus as "foreign", he says, prompting an immune reaction which may grow progressively stronger with each male child. The antibodies created may affect the developing male brain.
Andy Forrest, a spokesman for gay rights group Stonewall, said these studies leant further weight to the argument that lesbian and gay people should be treated equally in society and not discriminated against for something that's just as inherent as skin colour.
Share this page
There are no comments for this article, be the first to comment!
Post your comment
Only registered users can comment. Fill in your e-mail address for quick registration.