I prefer to have a mix of male & female players, at least 2 of each is good IMO - current group is 2f (edit) 4m*, & one of the guys is kinda campy so it (edit: kinda) evens out.

I don't particularly enjoy the Teflon Billy style "guy's night let's go to a strip club after" type game, and I probably wouldn't be willing to play in or GM a group that had a 'no girls' rule**, obviously as a mild-mannered straight guy I wouldn't suit the Ottergame game either... I've played in a 2/3 female game with Randomling the GM and it was good fun, though a bit lacking in hack & slash action.
*Oops, I have 4 m not 3.
**I wouldn't be comfy in a group with a no gays/blacks/Asians rule (explicit or implicit) either. Obviously if I'm playing with my old friends from high school, they're all straight white males from the Celtic fringe of the UK, but an 'old friends' game is very different from a public-recruitment game.