I agree with you. I hope that something that will tell other people what gender you are will appear in the future. But there is one thing... Don't display a picture of yourself... So that no one will send you such creepy and perverted messages.
I don't really see to much of a problem, so someone who doesn't know you doesn't know if your male or female whats the big deal. I wouldn't care if someone who didn't know me refered to me as she, although even as a male I'd rather not be called a brute.
You can right a bit about yourself in your profile if you find it that big a deal.