I tend to start with, "Hmmm, that doesn't make sense to me. As I understand it..." and explain. If they argue, I do tend to hold my ground and point out the flaws in the logic and ask them what GT research they've read. (Always none!) But I don't back down because I don't have a lot of patience for people who spout off about things they know NOTHING about, especially when what they're spouting about is my child! The Mother Tiger comes out in me.
I'm not saying that's good. It's just what I do.
With apologies to your son, I will say that I don't think letting it go completely is the right thing to do if she's teaching your child!
How do you *want* to handle it if it comes up again? What kind of help are you looking for?
