If the evolutionary survival of homosexuality is due to antagonistic pleiotropy then there has to exist a genetic basis for homosexuality. This is because antagonistic pleiotropy refers to when one gene controls for more than one trait where at least one trait is beneficial and at least one trait is detrimental to the organisms survival. In this case, homosexuality would be the trait that is detrimental to the organisms survival and there would need to exist another beneficial trait that is controlled by the same gene.
