Well you have a good point there Kist.
What I really meant was not safety, but closer supervision. Although I suppose this sort of thing needs to be evaluated on a case-by-case basis.
If I was in that situation, I would use the bf/gf sleeping over thing as a reward for my kid doing something good, like getting excellent grades. This way they associate sex not just with raging hormones, but with good achievements which take hard work to accomplish. I feel that this is a good structure to build on, but I also feel that it wouldn't be allowed to happen too often. You've gotta keep it special, and when young teenagers sleep together a LOT, the whole act just becomes sleazy.
Plus, that way I being a lazy father would force my horny teenage boys to get A+'s before they could get laid!
The earlier in the forenoon you take the sun bath, the greater will be the beneficial effect, because you get more of the ultra-violet rays, which are healing. - The Golden Age