*insert sexuality of your choice!
I've only ever been sexually attracted to men. But why? What is it about them?
I'm not attracted to all men, so it's not that I am irresistibly attracted to a single attribute all men have. But I have never been attracted to a woman, so it's obviously some attribute(s) no women have.
It's not genitalia, because I think I'd potentially be attracted to a man who had lost his genitals to cancer or similar.
Obviously each human has a pattern of likes/dislikes. I have never liked stereotypically 'feminine' things such as painting my nails. I would always choose climbing. But if I was asked to go to a nail painting hen do I would do it without fuss. Though my dislike of nail painting is something that is unlikely to change, it doesn't bother me to do this activity I don't enjoy in order to please a friend. The same cannot be said of getting into a relationship with another woman. So you can't reduce sexual orientation to 'just' a pattern of likes/dislikes.
What on earth is it that men have, which no woman I have ever met also has (excluding genitalia)?