It seems likely that CRISPR, or some improved version of it, will be established to be both safe and effective in the near future. Professor Stephen Hsu provides an analysis of the potential improvement from genetic editing compared to steroids.

Gene editing can make the genetically rare – the genetically common

Mike Israetel, a professor of exercise science at Temple University, has estimated that doping increases weightlifting scores by about 5 to 10 percent.

Compare that to the progression in world record bench press weights:
361 pounds in 1898,
363 pounds in 1916,
500 pounds in 1953,
600 pounds in 1967,
667 pounds in 1984, and
730 pounds in 2015.