Researchers have found that homosexual men tend to have a greater number of older brothers than heterosexual men.Which hypothesis has been proposed to account for this finding?
A)The mother's immune system is exposed to male-specific proteins during pregnancy,which then limits the amount of testosterone available during later pregnancies.
B)Parents tend to deemphasize masculinity in young sons if they already have several sons.
C)Being raised with older male brothers influences the developing sexuality of male children.
D)Younger brothers eventually inherit a gene that predisposes them to homosexuality.

Question

Quizplus · Accepted Answer

This hypothesis, known as the fraternal birth order effect, suggests that when a woman becomes pregnant with a male fetus, her body may produce antibodies that fight against male-specific proteins. These antibodies could cross the placenta and affect the fetal brain, potentially altering sexual orientation. As more male fetuses are gestated, there is a greater chance that the mother builds up these antibodies, leading to a higher likelihood of homosexuality in subsequent male offspring. This theory has been supported by several studies, though the exact mechanism behind the fraternal birth order effect is not yet fully understood.

Researchers Have Found That Homosexual Men Tend to Have a Greater