All were white and none were twins, he told the journal New Scientist. He studied the family backgrounds of 302 gay men and the same number of straight men.
Now Canadian psychologist Ray Blanchard says the answer depends on how many older brothers a man has. However, the researchers think their findings are linked to what happens in the womb, rather than the effects of growing up among older boys.įor decades, academics have argued over nature versus nurture - whether individuals are born gay, or become gay because of where and how they grow up. Gay men had more older brothers, on average, than straight men, a study has found.įor every older brother a man has, the chances of him being gay increases by 33 per cent.
Boys with older brothers are more likely to be homosexual than those with sisters, younger brothers or no siblings at all, according to research.
