I'm backwards on this, I am predominatly attracted to females but with men it is more of a lust thing but I can be more open with females.
Seriously the best thing you could do is seek counselling, I know some of us have "pride issues" but no one can help you unless you choose to help yourself. Another option would be to read up on gender roles or sexuality books.
What happens sometimes is we close our minds, its a whole mind over matter thing. I would say seek a woman who is open to a sex based thing first, see if it does anything, if not then maybe you are bi or possibly gay.
I'm gender neutral, I portay both charactheristics of a male and female but I am not confused, I just can't stand being a female but I don't want to be a male either. the best thing you could do is educate yourself as well or look for online groups.
I think if the right woman was around, if she touched you, you would get an erection but she would also have to be patient and you would need to free your mind.
Anyway, good luck in your decision~! I know its hard to picture ourselves with the other sex but I also think you need to expierence with both to figure out where you stand. you won't learn from fretting over it.