I have longed believed it was CONGENITAL, but NOT Genetic. This was because of my studies of the brain "software" where I discovered the personality was built up of a hierarchy of 'binary settings" Animate vs Inanimate, animal vs human, man vs woman, heterosexual vs homosexual, . . . There were at least six of these. There is a NORMAL setting, but in utero "accidents" or exposure may affect the settings, leading to some "quirks" and "personality disorders"--including Homosexuality ---I believe that some conditions that CAN produce these accidents may be hereditary in the mother.