DC's school has brief segments as young as kindergarten that address the human body from a scientific standpoint. We've always answered questions in a matter-of-fact way, but the school's offering was going beyond what we had discussed, so I got each child an age-appropriate book and left them strewn on their bedroom floors. Both read them avidly. DD6 was very blase, asked some factual questions, made a few observations and that was that. DS8 was clearly interested, but disinclined to discuss matters and giggled at one part, which made me grateful that I hadn't left it until he was older when he might have giggled at the whole thing.
