Who's growing the baby?

It's a little hard to figure out exactly how to tell a two year old that he's going to be a brother.  I thought about it a while and then one day I just had the conversation.  It went like this:

Me: Mommy's growing a baby in her tummy (insert pat of tummy here)

Carter: NO, I grow baby in belly!

Me: ok

The next conversation went something like this:

Me: Mommy's growing a baby in her tummy (insert pat of tummy here)

Carter: NO, I grow baby in belly!

Me: Where will the baby sleep?

Carter: on the floor (he later changed that to in her bed)

Me: Will you share your toys with the baby?

Carter: Noooo (which he later changed to yes)

It's going to be interesting. I think little Carter may get his world turned upside down.