I think one of the best ways to protect girl children is to send them to the Unitarian Universalist Our Whole Lives course, which teaches them that their bodies belong to them and prepares them in advance for a variety of scenarios--something Health class definitely does not do.
One girl who took the class was at a sleepover when the host's brother started touching her in her sleep. Because of what she'd learned, she didn't keep the secret in shame--she jumped up, started shouting, and pointed the finger at him.
With the whole world telling women we are here for at pleasure of men, it's hard for a parent to get another message across. But women need to realize that they are both sexual beings and that that aspect of their humanity is entirely theirs to control.
Rape culture is a huge problem worldwide. Boys as well as girls benefit from straight talk about sexuality, which parents are often embarrassed to give.
I sent my daughter to that class against her will. She thought she knew it all already at age 12. Later, in college, she told the story to her Female Sexuality class full of accomplished and highly intelligent women. One cried. One went home and wrote "My Body Is My Own" in big letters on her wall. No one had EVER told her that before.
Another difficult aspect of this for parents is not trying to control their teen girls' sexuality. Give them all the information they need to protect against pregnancy and sexually transmitted disease, and then reaffirm the message: your body belongs to you. I will not try to control it. You decide when you want to have sex. But please don't do it for a boyfriend or to keep up with a girlfriend. Do it when you feel ready and eager within yourself.