I think it's a western thing, sex is just a scary subject that makes people nervous for no reason and leads to all kinds of crazy rules.

Kids ride bikes in the street, swim in deep water, climb trees and take all kinds of risks but it's appreciated that it's an important part of growing up, learning to be responsible and understanding how things work.

Fundamentally like any organsim our primary purpose for existing is to mate and have children to carry our genes on and yet although this is central to our reason for existing as a species its the one subject people are afraid of. The end result is teenage pregnancies and people having confused and often fearful views of sex. People end up reaching that magic invisible line when it becomes legal and then just sort of stumble into being sexual. Some get pregnant, some are scared and feel pressured to have sex while others think sex is what they saw in a dirty magazine or video they found hidden under their older brothers bed. Then there's 10 years of confused relationships until they figure it all out and settle down into a healthy stable relationship.

I'm sure there are more sensible and better ways of handling something so fundamental and important but I don't see society facing up to it any time soon.