I have had the exact same questions from my DS. My sister recently had a caesarean, and when DS asked how her babies (she had twins) came out, I said the dr cut a whole in her tummy to take them out. 'Phew,' I thought, thinking I'd got out of that one easily. But, I am also pregnant. A few weeks later, he asked if he could see the hole in my tummy after our baby is born. 'Damn,' I think, 'Now I'm going to have to explain!' So, I said that babies usually come out of their mummy's bottom and that's probably how our baby will come out. DH is horrified that I used that term, but my kids don't know the word vagina or anything else resembling it. They know that boys have doodles and girls don't - they haven't asked what girls have instead, so I just refer to anything down there as 'bottom'.

As for how the baby gets in there, mummies and daddies make the baby (he hasn't asked how!). But you're pretty much always in mummy's tummy until you're born - this came from him asking where he was when looking at photos of our wedding. I said he wasn't born yet. 'So where was I?' I ended up saying that he was still in my tummy, but so small that I didn't even know he was there!