My 6 year old asked me the big question. I wasn't prepared to tell him. So I told him that it was like a plant or flower. A seed gets planted and the baby grows...etc. He asked where the seed comes from, I said the dad. Then he kept asking how the seed got INTO the mom, and I was trying so hard to avoid the question. I just kept telling him that I would tell him when he was older and changing the subject. After much thought and a day or so later, he came up with his own conclusion. He came in and asked, "so does the dad sneak it into the mom's mouth when she is sleeping and then she swallows it? Is that how it gets in the mom's tummy?"