S3x is an open topic in our house. We don't see the point in making it a taboo subject, or shying away from the topic. I would much rather our girls know the facts rather than hear school yard gossip. I want them to be comfortable talking about it to me. Same with puberty. I mean, we have a house full of girls apart from dh, its a topic that will inevitably be a common thing! It also depends on the child. Dd1 has always been wise beyond her years and asks questions that most kids her age probably wouldn't even consider. She asks questions so we answer honestly. Dd2 on the other hand is much more resvered with stuff like that. She will ask about something if it sparks her interest but s3x and puberty hasnt even appeared on her radar yet really, unlike dd1 at the same age. She will ask when she is ready to learn.