Im a big fan of 'harm minimisation' (i think its cause of the nurse in me), basically it means, you can tell people black and blue not to due something, it might work on some, but wont work on everyone (nothing does) so for those it doesn't make sure if they are going to do it, they do it in a safe way. this isn't just in terms of sex, also things like needle exchanges so people who do use them use clean needles and dont share etc, to limit infection.
in terms of sex, a safe way is with 2 consenting adults, ill hopefully make sure my children dont rush, they do it with someone they trust and respect, dont have to love them, but if both parties are of sound mind and consent. and both take resposibility for any consequences of their actions (same with anything), and that means protection as consequences include pg, sti's etc..

simply, i wont be pushing it and encouraging it, but will help them do it in a safe way if they do, and if that means supplying them with condoms fine.

even simpler.. no i dont think teaching absinence works