If you’re the type of person that likes to talk about your genitalia and/or the genitalia of others in nasty ways or enjoy harassing people based entirely on what sort of genitalia they have then Halo 4 may not be a safe place for you. In an recent interview, members of Halo 4’s development team made it clear that sexism within the multiplayer portion of the game will lead to a lifetime ban. That means forever. If you enjoy sexism, you’re going to need to reserve it for the single player campaign. Sorry.
While some may see this as drastic, I think that it’s probably not a bad thing since mulitplayer in most every game has gotten rather vile and gamers aren’t quite able to moderate their peers all that well. I’m sure the free speech freedom fighters will arrive in droves to argue against such a punitive measure, but is pushing etiquette and respect really that bad?