If a part of a person is attracted to that of the other gender, then that person is at least, in that capacity, heterosexual. Even if their minds disagree with physiology--nobody is purely homosexual/heterosexual.
You keep bringing it to a point beyond sexual preference though, which is all that heterosexuality describes by its definition. Think about it this way, you could be a heterosexual your whole life and never once have sex or fertilize an egg and thus never contribute to the next generation. Heterosexuality is not what is vital for life continuing on, sperm fertilizing an egg is ultimately all that is required, the sexual preferences of the provider of the sperm or egg does not matter at all.
Last edited by MikaDubbz,