Deaing with sexual harassment is something that girls need to learn to deal with. It would be great if we lived in a world where no one infringed on another's rights, but the reality is that, until the behavior modification chips are implanted, we'll always have that. Your two options are pretty much limited to taking it or dealing with it. Taking it may cause the attaceker to eventually give up in frustration, but the problem usually intensifies before it gets better. Sometimes confronting the attacker is the better path.
There are three basic arenas to deal with harassment in: in real life, online gaming, and social media. Social media is actually the easiest to deal with, and that can include any blogs you are on. If someone is being abusive to you, you can always block the person and notify the administrator. If the abuse is persistant grab some screenshots and show your parents or guardian, an e-mail the screenshots to the admin. Some blogs allow you to block the IP adress of the person, which means that they can't harass you from that computer again. If it gets serious, such as death or rape threats, get an authority involved ASAP; it's most likely just some troll, but it could be something that someone needs to take seriously, so do so yourself.
Gaming harassment is harder simply because it requires a thick skin and some ability to shoot. Threats during the game are meant to intimidate; they either cause the person to doubt herself, makng her less likely to shoot and therefore into an easier target, or to anger the person, costing that person accuracy and therefore less likely to hit. Either way, the harasser wins by making you an easier kill. You stop playing because it's no fun, and theyget new victims. You lose, they win, and that's not acceptable.
This is one case you need to ignore what the person is saying, track them down, and kill them. Period. Don't lose your cool, don't engage them in a verbal war, just slaughter them. Repeately if need be. I rarely encourage camping, but I'm more than willing to make an exception in this case, but leave the other players alone just to make a point. You'll find that you gain a lot or respect for dealing with the problem quickly and succinctly, and others are more willing to help you deal with those jerks in the future. You'll also note that it's an easy way to rack up kills as players that rely on harassment to soften up their targets usually aren't that good.
In real life, it's a lot more complicated. If you can videotape the harassment, so much the better; it's hard to deny vidoe evidence. If you can't, confront the person head on; it may be difficult, especially the first couple of times, but if you can cut down the harasser verbally you'll earn respect from others as well as discourage others from doing it as your reputation spreads. It does mean you'll have to deal with more agressive attackers, but you'll find that people that are willing to stand up for themselves gain allies willing to deend them easier; people also tend to band against bigger threats. You may want to learn some basic self-defense for those that turn violent, but this is well within your ability to deal with. Harassment is something that everyone needs to learn how to deal with, and how you deal with it now sets the stage for later. So figure out how youyou want to deal with it and do it. But don't just take it; that way is not as easy as you would think.