While I was pregnant with his sister, my son never asked any questions - he was 4. Once he entered kindergarten - he waited until I was in the busiest intersection in Columbus, OH, making a left no less and asked me how my daughter "got in there". I told him I'd love to answer his question but it would need to wait until a little later as he deserved more attention than I could give him while driving. DH decided it was his job to tell him (and only the questions as asked since he was not quite 6) - so he sent me off to the store to buy bread and milk. As I entered the house I heard my son say to his father "Oh, Dad, mom is NOT going to like THAT!"