I'm a male that plays mostly female characters. I couldn't say exactly when it had become a habit, but there certainly was a time many years ago in which I'd started to play (almost exclusively) female characters, and I think it had simply become custom for me. Self-perpetuated until I became more comfortable playing women than men. I couldn't say for certain how well I play them, but I'd like to think I've picked up good "habits" and conceptions on how to play the opposite gender better over the years.
I've also developed, thankfully, an ability to separate my sexuality from my characters', so I don't experience much trouble with having my female characters pursue relationships with men (IC/OOC or otherwise).
I've also developed, thankfully, an ability to separate my sexuality from my characters', so I don't experience much trouble with having my female characters pursue relationships with men (IC/OOC or otherwise).