Thirteen is way too young to be having sex of any kind with anyone, older teens and college boys especially. Your friend is engaging in very dangerous behavior, and she's at risk of contracting sexually transmitted diseases and of becoming pregnant. She is also damaging her self-esteem and is at significant risk for severe emotional problems as a result of her sexual behaviors.

The older boys who are having sex with her are also potentially punishable by law for rape in most states because of her age. Any older teen or college boy having sex with a 13-year-old girl is sexually abusing her.

I know that you must be very worried about your friend and you have done the right thing by trying to persuade her to stop having sex with these boys. But I think it will take more than your e-mail or talking to her as a friend to stop her self-destructive behavior.

You need to talk to your parents or a trusted adult about her behavior. Get them involved and have them notify her parents of the situation.

There is something seriously wrong with your friend emotionally that is forcing her to act in this inappropriate, risky, shameful, self-hateful way. You can be her friend but you can't save her from this destructive path she has taken all by yourself. Please talk with some or all of the people I suggested.

She may tell you that you're not her friend anymore, but you have to be brave and think of her safety and health above any hurt feelings you may get from what she tells you. I'm hoping you can summon up the courage to tell the right adults about this. She is in big trouble that could affect her entire life.