Because this kind of conversation, first thing in the morning, is pretty hard to NOT find hilarious. And when I say first thing, I MEAN first thing. The boy sat upright in the master bed, surveyed the room, and launched into this line of questioning in a still-sleepy, gravelly voice.
"Mom. Mom. MOM. What you doing?"
"I'm changing the baby's diaper."
"Because she pooped."
"Oh. [pause] Yellow poop?"
[struggling to answer as gravely as the question was asked, you know, out of courtesy] "Yes, son. Yellow poop."
"Not brown poop?"
[starting to lose the battle] "Um, no. Not brown poop."
"Oh. [another pause] I have brown poop, mom?"
"[AHEM] Yes. Yes, son, your poop is brown."
[And I should have seen it coming.] "Why, mom?"
"Just ... just because."