A man who has a homosexual orientation is most likely to have a brother who is also homosexual if that brother is:
A)an identical twin
B)a fraternal twin
C)older
D)adopted

Question

Quizplus · Accepted Answer

Identical twins share the same genetic material, so if one twin has a homosexual orientation, the likelihood of the other twin sharing that orientation is higher. Fraternal twins also share genetic material but not to the extent that identical twins do, therefore the likelihood of having a homosexual brother is lower. Age and adoption are not factors that significantly impact the likelihood of having a homosexual brother.

A Man Who Has a Homosexual Orientation Is Most Likely