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.

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Inthusan Lingeswaran · Accepted Answer

Final Answer : D, Explanation :  Studies have found that if a man is homosexual, his twin brother is more likely to also be homosexual if he is a monozygotic twin (sharing 100% of their genes) than if he is a dizygotic twin (sharing only around 50% of their genes). This suggests that genetics may play a role in sexual orientation. Other studies have also found that there may be certain genetic markers associated with homosexuality, although this area of research is still not fully understood. Choice A is not accurate as estimates of the percentage of people who are homosexual vary widely across cultures, and there is no consensus on a specific percentage. Choice B is not accurate as most homosexual men do not have homosexual fathers or grandfathers.

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