Why are men with older brothers,but not men with older sisters or those who are only children,more likely to be gay?
A)Mothers are more likely to unknowingly treat their youngest sons like daughters.
B)A mother's heightened immune response with subsequent male-fetus pregnancies affects brain development.
C)Older brothers are likely to deride and belittle the youngest brother,creating a more sensitive,fearful,and confused individual.
D)Older brothers are more likely to protect and guard the youngest brother,shielding him from rough-and-tumble play and traditional masculine rituals.

Question

Quizplus · Accepted Answer

The theory is known as the "older-brother effect," which suggests that a man's sexual orientation is linked to the number of biological older brothers he has. One explanation for this effect is that during pregnancy, a mother's body may develop antigens that affect the development of the brain of male fetuses, which could lead to a greater likelihood of homosexuality in males with older brothers. This explanation is supported by studies that have found that men with older brothers have a higher likelihood of being gay, but men with older sisters or those who are only children do not show the same effect.

Why Are Men with Older Brothers,but Not Men with Older