I'm a male gamer. I've had other players request I do obscene acts for them, been called every name/curse in the book, and some not in the book, pretty much everything you've described here (No one has requested nudes from me, yet).

What you will soon learn about people in general, is that when shielded by the anonymity of an avatar/gamertag, their basic decency no longer becomes a requirement to succeed in society. It has less to do with you being female, than it does to do with the younger generation of children being brought up in this type of gaming enviornment, and it becomes a self-fufilling prophecy.

Unfortunately, your best bet is going to be to manually mute the players that are harassing you. There is a massive group of people that are not going to change their behavior just because you asked them to. I think it's important to manage your expectations.