Does everyone have a brain?

On the way to school today, Andrew and Elizabeth were giggling in the back seat. I asked what was so funny and Andrew replied "I don't know!" but they kept on laughing. This is not surprising since he, at 4.5 and she, at 15m, laugh at pretty much nothing together quite often.

But then, he asked her a question... and she nodded. He stopped laughing and got VERY serious. "Mommy!!! Mommy! Lizzie nodded! She knows what I asked and she said YES!" I said "yes, it does look that way - she nods to me quite often lately" I reminded him that she's been communicating by signing "milk", "more" and most recently "bird" -- and he said "Mommy, does everyone have a brain?" to which I replied in the affirmative... and to which he responded with "Whoa... even BABIES?!" again to which I responded in the affirmative.

I guess he thought that the brain came later? That one needed to grow a brain? and that it appeared much later in life... like when you're, say... 3 or 4?

Oh, what a wondrous revelation to know that his sister has a brain and can even THINK and RESPOND to him! Life is miraculous, no?