Interesting questions...

Last night I was asked an interesting question by Aiden (and yes...during bedtime).  He is laying in bed and yells out, "Does it hurt to push out a baby?"  What?!? Now when he says "push out", he is talking about from your tummy.  He has no idea what area the baby actually gets pushed out from.  I tried to explain that the baby grows in the Mommy's tummy and then just comes out.  Trust me... they have asked for more details but at this point I have just changed the subject.  Why don't my boys believe that babies come from the stork.  I am not sure how to explain these types of things to my kids, especially boys.  Lately they have been very interested in babies so I am now getting lots of questions about how it all works.  What's a Mommy to do??