Big Brothers May Make Boys Gay, Says Study
PARIS (AFP) The more older brothers a boy has the likelier he is to be a homosexual, according to a theory aired in the British weekly New Scientist.
A Canadian researcher has found that boys with a statistical average of 2.5 older brothers are twice as likely to be gay as boys with no older brother, while a boy with four older brothers is three times as likely to be gay.
The study, published in a specialist journal, Archives of Sexual Behavior, was led by Ray Blanchard, a psychologist at the Centre for Addiction and Mental Health in Toronto, Canada.
Blanchard broke ground in gender science a few years ago when he was struck by a strong link between homosexuality and older brothers in a group of 302 gay white men.
His notion was at first ridiculed but is now accepted by many in his field, and other studies have taken this idea further, suggesting that the link exists regardless of culture, New Scientist says.
Why there should be this association is unclear, says New Scientist.
One idea is that male foetuses trigger a response in the mothers immune system through an antigen, H-Y, that only exists in males and is believed to play a role in sexual differentiation. …