I've seen papers where CRISPR was used to modify mouse embryos so the mice grow up to express certain proteins in certain organs (the proteins were useful for m

I've seen papers where CRISPR was used to modify mouse embryos so the mice grow up to express certain proteins in certain organs (the proteins were useful for modeling disease). The differences between this and human modification are probably that nobody minds losing a bunch of mouse embryos, and that a lot of human traits are polygenetic and thus not a simple matter of adding a single protein. That said, it's only a matter of time until someone unscrupulous demonstrates human gene modification in some poorly regulated polity.