explaining where baby "comes out" to big bro

cocoriffey

For those of you with more than 1 kid, how did you go about explaining where the new baby comes out? My son is 4, and he keeps asking how the baby will come out of my belly. He thinks my belly will "break apart" and the baby will pop out. I've told him that I will go to the hospital and the dr will help me get the baby out, and that mommy's have a special place where the baby comes out of and that it's private. Is there anything else I can tell him without being too graphic? He's really preoccupied with private parts right now and I don't want to give him one more thing to be thinking about it, but I want to answer his questions honestly. He was only 2 when his sister was born, so I didn't have to deal with this then. Any suggestions are welcome! Thanks!!