The Probability of a Man's Becoming Gay Rises Significantly According

Multiple Choice

The probability of a man's becoming gay rises significantly according to the number of older brothers he has.The reason for this "brother effect" may be

A) that parents with many male children secretly wish for a daughter and encourage feminine behavior.
B) that a child with older brothers behaves differently to get attention.
C) that the developing brain responds to having so many males in one house.
D) changes in the conditions within the womb caused by previous male pregnancies.