People are ignorant, but most of the time I think their intentions are pure. I have not yet gotten the adoption question outright, but I am sure I will. Sometimes people will comment on how DD is "exotic" looking. Not sure if I should be offended by that or not, but I know they mean it as a compliment so I try to just ignore it. I can't quite say for sure how I will feel when some one asks if DD is adopted but I am going to try my best to let it role off. Hanging on to it as an insult will really only ruin my day. I am sure whoever asks will have forgotten within about 5 min! Probably best to just let it go. Lord knows I have said my share of stupid things before too!
I suppose if DD was old enough to understand and be offended by the comment, I might feel differently but would still try to downplay it for her sake. Just try to focus on all the times you get people commenting on how handsome your son is!