would it be a good time to get one of those toddler friendly 'how babies are made books' (mummy laid an egg, where willy went) for DS,21 months, as his baby sister is due next month.
My parents were very honest about where babies come from at an early age and I'm not sure when to start with him. I know we have to talk to him about it too, but the books do look like fun and a way of making it more matter of fact.