POLL: Americans Closely Divided On Homosexuality's Origin

Gallup has a recent poll (May 8-11, 2014) on attitudes of Americans towards certain social issues and the question of the origin of homosexuality continues to be a tight affair, with 42% saying it is innate and 37% saying it is environmental. The question's answer has important public policy implications because people who believe homosexuality is innate are vastly more likely to support LGBT equality. Since 1973, the question of whether homosexuality is a mental illness has been a settled one.

The contention on this question of a person's sexual orientation possibly reflects a lack of input from the scientific community, which historically has not shied away from offering its opinion on lesbian, gay, bisexual, or transgender (LGBT) issues and questions. The American Psychiatric Association removed homosexuality from its manual of mental disorders in 1973, giving credence to the nascent gay rights movement at the time. 

U.S. public opinion about gays has changed drastically in recent decades on the issues of marriage equalityand LGBT acceptance as a whole, possibly related to the fact that three in four Americans say they have a friend, relative, or coworker who has told them that he or she is gay. Though being gay as the result of genetics or other factors before birth has become a considerably more mainstream belief and is now mentioned by a plurality of Americans, it is still one held by slightly less than half of the U.S. population. This disagreement seems likely to continue as long as the scientific community remains agnostic about the question.

 What do you think? Why are Americans still divided on this question when they have clearly made up their mind in support of marriage equality and LGBT equality overall?