Like the guys trying to prevent the use of “autonomous” armed vehicles in warfare (robots). I honestly don’t believe it can be done. I’m far from convinced it is even the right thing to do.  Trying to get all nations to do “the right thing” (once you’ve formed an opinion of what the right thing is) with any new technology puts me in mind of an old saying:

“That is all very well, but who is to bell the Cat?”

Æsop. (Sixth century B.C.)  Fables.
The Harvard Classics.  1909–14.

Medical specialists urge more debate on gene-editing technology