Why do Butch s seem to be prevalent?

In Chicago, I'd say that there are an equal amount of butch vs femmes. I consider myself to be more femme than butch, though I have my in-between days. I believe that the reason behind butch is all about comfortability. That is who they are, and that is how they like to dress. I couldn't judge someone based on appearance, and frankly I'm not that way so it's hard for me to pinpoint exactly the reason behind it.