I was replying to this part of your comment:
"even people that _are_ lactose tolerant often lose tolerance as they age, so it seems like this could have wide appeal."
My point is that people who are lactose tolerant as a child will have the same genes when they are older. So gene editing should have no effect, unless the mechanism is more complicated somehow.
Oh I see, that makes sense. Ya, I'm not sure how it works, maybe it has something to do with changing gene expression as we age? Ie, not the genes themselves changing, but the way that they are used / neglected? And then if that's the case, what would that mean for people that had taken this treatment? Perhaps they would see the age-related drop off, or perhaps it's different for some reason.