Birth Control for young girls

[Cloud]

At what age do you think it appropriate for your/a young teenage girl to be on birth control?

Do you wait until they come to you and say they're sexually active? (may be a loooong wait!)

When they start dating?

When they first menstruate?

After they get knocked up for the first time?

I wish that it was culturally normal for all girls, after they start menstruating, to be on birth control, before they're sexually active. Not to encourage sexual activity, but as a preventive measure, and a matter of course. I don't necessarily mean the pill, because I don't think they would take a daily pill, but some of the longer-lasting alternatives available now. They would have to affirmatively go off their birth control to get pregnant.

I know that's a pie-in-the-sky, but think of how many teen pregancies, and poverty-level families that would prevent.