I was going to leave it, but I think I'll say a little more. It seems to me, that when you try to deal with absolutes like that with an older teen (I'm not talking 12 or 13 here), you are more or less abdicating your responsibility as a parent. You set an absolute that you know (or at least highly expect) is going to be broken, and then when it is, you can wash your hands, and say, "I told you so."
I'm not saying that you should friend about it. I'm more saying that you have to help lead them to all of the best information you can, and hope that they then make good choices for their life.
Teens of that age are in a tough place. They are too young to really make good choices, and too old to accept "because I said so" as a good reason to do, or not do, something. It calls for using all of the things you've learned in your life, and about them as they are growing up. It's the best chance you have, in my opinion.
This comes from someone who didn't have sex until they were engaged, so I know it can be done. But.....
From what I have seen in the trash, I'm fairly confident that S22 and probably 20 have.... I haven't heard of any grandkids, so at least they seem to be using a small amount of sense!
