Question

According to recent research, a male may be at a greater likelihood to be homosexual if he has:

Answer 1

The correct answer is older brothers. 
Research suggests that if a boy has older brothers, there is a higher chance that he will be gay than those boys who don't have older brothers. This is probably because he will be surrounded by young boys and men since his earliest childhood so he may or may not develop certain feelings for the same gender.

Answer 2

According to recent research, a male may be at a greater likelihood to be homosexual if he has older brothers.