"Are you his grandmother?"
The thing is, the kid who asked was so young, and so well meaning, and he was so mortified when I laughed and told him that, no, although he is Grand, he is not my Grandson, I thought he might actually implode. I couldn't get angry at him for being so tactless, because I have stories about things I said to people when I was that age that still keep me awake at night. Perhaps now that I've been asked this question (twice), I can let myself get over my long-ago mistakes. Apparently I need that missed sleep.
I still feel kinda like I want to cry, though.