*shrug* Really, why does any article of clothing or action have an 'assigned gender'? It's just what people are used to. They rarely make any actual practical sense. If they see something different, they question why.
I carry a wallet in my back pocket because I don't like purses. My mother told me to, "Stop doing that, it makes you look like a dyke." I just considered it more practical, and hadn't thought about the social implications it might have. Oh well. I like my wallet.