he's only 5

On the way to the library this morning Carson asked me, "How do you stop having babies?"
(I'm trying not to show shock on my face.)

M: What do you mean?
C:  When you don't want anymore babies what do you do.  I only want five.
M: Well... (I can't believe I'm having this conversation with a five year old!!)  When the mom doesn't want anymore babies she can take some medicine so she won't have anymore babies.  It's called birth control.  (In retrospect I probably shouldn't have told him what it was called.) 
C:  OK.  I don't care how many babies I have, I just don't want like 12.

I can't imagine what he might ask me when he's 10.