That " DUH!" moment

Mike, who was in a particularly affectionate mood, was cuddling with Mackenzie on the bed when this conversation took place:

Mike: I just love you so much. I wish I could keep you this size for ever.
Mackenzie, focused on the TV show she was watching, says nothing.
Mike: But if I kept you little, I never get to see what you grow up to be.
Mackenzie, still unaffected by the conversation,remains silent.
Mike persists: What do you think you'll grow up to be?
Mackenzie ( finally looking at Mike): Tall.