The maternal immune hypothesis suggest that a male child could be predisposed to homosexuality when

a. his H-Y antigens cause his mother to release too much estrogen, exposing his fetal brain to feminization.
b. his mother’s antibodies attack his H-Y antigens, preventing the fetal brain from developing male-typical brain structures.
c. a fetus develops an immunity to the effects of maternal testosterone, preventing masculinization of his brain.
d. his mother is exposed to certain vaccines that increase her immune response, preventing certain fetal structures that are central to a masculine brain from developing.

Answer: b: his mother’s antibodies attack his H-Y antigens, preventing the fetal brain from developing male-typical brain structures.