This technology might not work at all, or it might be highly effective after refinements.

If it is highly effective moral arguments are moot. Genetic engineering will be like nuclear weapons. A nation that desires to be competitive or have economic dominance won’t have any choice, it will be forced to adopt its usage (or be left behind).

Even agreements to control nuclear weapons that could cause human extinction still leave nuclear weapons in the hands of many major nations (and a handful of tiny ones) so international agreements have little chance of curtailing genetic engineering.