Having older brothers increases younger brother's chances of being gay
New Delhi : Among two brothers in the house, the younger one has more chances of growing up as gay, claimed a new research. It says that having a son triggers a physical reaction in mums, making it more likely that later boys will grow up to be gay.
The research further explains the science behind this unbelievable fact. According to scientists, having a male child triggers an immune reaction in the mother that can alter the brain of the growing baby.
The study was conducted by a group of researchers at Toronto University. The findings of their research have been published in the Proceedings of the National Academy of Sciences.
Authors of the study say that the research is a major advance in understanding the origins of sexual orientation in men by providing support for a theorized but previously unexamined biological mechanism—a maternal immune response to a protein important in male foetal brain development.
They further add that research begins ‘to explain one of the most reliable correlates of male homosexuality: older brothers.’
However, the good news remains with the fact that chances of turning a male child into a gay remain low at 3 per cent, for someone who has three older brothers, the chance doubles to 6 per cent.
While girls have two X chromosomes – the genes that dictate a child’s biological sex, boys have an X and a Y chromosome.
And it is the ‘Y’ chromosome which creates the biological differences that make a child male that triggers an immune reaction in a mother.
In response to having a male child, the body reacts against the Y chromosome and creates an antibody called anti-NLGN4Y.
After having a son, a woman builds up a large supply of the antibody, and this can affect the brain development in later male children.