How do we get you a little brother?

For the last year or so I've asked my son a certain question every now and then. "Would you like a little brother or a little sister?" And every single time I ask him this he emphatically and without hesitation answers, "NO!" When asked why he all of a sudden wants a brother now he said, "because I like brothers." Okay...
So I say, "So how are we going to get you a little brother?"
He replies, "I don't know."
"Should we BUY you a little brother?"
He says," YEAH!"
"Where do we buy little brothers?"
"Um...I guess we could go to the baby store and buy a baby brother there," he answers.

I am once again surprised and somewhat bewildered of how children think. There's never a dull moment, that is for sure.