Question for those who may know:
It's fairly common to sneeze when confronted with bright light; it has to do with your eyes watering and tickling your nose or something. (Edit: Or perhaps it's just genetic. No one seems sure. I have this trait, anyway.) But why in the world does my son sneeze, just once, almost every morning, after his first bite of toast? It's a mystery to me. But at least it's sort of cute.