[Donnie's legs stop their near manic fidgeting as Rue squeezes his arm at least, so perhaps it's doing something good? Internally, Donatello can feel his nerves calming a bit. It's not as good as when a brother full-on shoves him over and lays atop his shell, but it's serviceable.]

Perhaps genetically. There are plenty of exceptions. [This conversation is unhelpful, however.] His reaction doesn't matter, in the end. The problem is the memory loss.

Have you heard of this happening to anyone else?