many people believe that it is unfortunate to discuss causes of homosexuality and bisexuality without discussing causes of heterosexuality, too. although it is easy to understand why heterosexuality exists (heterosexual sex produces babies), that does not explain how the brain develops to produce heterosexual people. heterosexuality, homosexuality, and bisexuality all have causes, and some people believe that to discuss only the causes of homosexuality and bisexuality suggests that there is something wrong with people who have those orientations.