What will happen if you ask clear questions? You'll probably get answers.
Snark aside, I'm assuming you mean banning your kids from having sex. In my experience, parents have little control over it. If your teens want it, they'll find a way; you can't monitor them 24/7.
And they may resent you depending on how far you try to control them, so I'd advise parents to exercise caution. Talk with them and express your views about the risks and dangers of engaging in it too young, but in the end, your children ultimately choose when it happens.