Gay gene means: Gay gene: The gene on the X-chromosome that is responsible for male homosexuality. This “gay gene”, also known as homosexuality 1 HMS1, was used to refer to the male sexual orientation genes. The chromosome band in which it was found is Xq28. Dean H. Hamer, along with colleagues made the original claim about the “gay genes” in 1993. It has not been confirmed by independent sources that a gay gene exists, and there are still questions about it.
(in Medical Dictionary)