Tim and I have always been very open with Josh when it comes to his body and ours. We use correct terms for everything and encourage discussion and questions. I guess that's what we get for the following story.
I'm standing in the kitchen and Josh comes up to gives my bulging belly a kiss. He then looks up and says, "Mom, did you buy your boobs?" "No," I responded. He then comes back with, "Well, then where did you get them?" To which I explained, "That's just how it is. Girls have boobs and boys have a penis." I then shrugged my shoulders. He looked at me, shrugged his shoulders and walked off. He hasn't returned to the subject again so I can only assume that my response was sufficient for a 3-year old. I can't wait to see what questions a 4-year old will come up with.