I don't think I've ever played a cross-gender character, as a DM or a player, though I have one player who is doing so in one of my games now.

Oh wait, you mean playing a character whose gender doesn't match your own in real life? Ah, if so, I took that a bit differently. I thought you meant a character who was one gender in game, and pretended to be another gender in game, or had themselves changed deliberately to another gender in game.

Multi-gendered, non gendered, male, female, transformable gender, one of a multiple gender race, i've had characters of races with all of those types of genders, that sort of thing never even occurred to me that it could even be an issue.

In my own gaming experiences, I DID see a lot of anti-female comments and attitudes, which is what prompted my reaction described above.