Well, I don't think it would be as easy as trying it and forgetting it as soon as it is found to be detrimental. its not like proper channels would not exist to make sure any form of procedure and long term results are safe in the long run for a large percentage of people ( it can never be 100%-at least I wouldn't think so- if thousands of people a year die for no good reason for taking things like Tylenol...). There is plenty of animal experimentation left (I have no issue whatsoever with that sort of thing honestly) and once it is determined to be safe enough by whatever standards they make for such a thing (wonder if any such standards do exist) they could try it on someone who would be screwed either way (say, someone with severe muscular atrophy conditions) and see the mid and long term results. They already have practices in that order in the form of experimental treatments which might or might not save your life in extreme conditions.... I am not geneticist however there is also the issue of whether such a thing would be inherited by children in the future, something which might or might not be a problem.