What Evidence Is There, If Any, That Homosexuality May Be

What evidence is there, if any, that homosexuality may be partly the result of genetics?

A) We know that 10% of people are homosexual across cultures.
B) Most homosexual men had homosexual fathers or grandfathers.
C) If a man is homosexual his twin brother is more likely to also be homosexual if he is a dizygotic twin than if he is a monozygotic twin.
D) If a man is homosexual his twin brother is more likely to also be homosexual if he is a monozygotic twin than if he is a dizygotic twin.