I never understood the banning genetic enhancements argument. I think its based on a 1960's public view of genetics. Considering the things science can do now to embryos without them being turned into future megalomaniacs. Would the audience of the 1960's consider test tube babies 'genetic enhanced' people? The canon in the Star Trek universe is humans can live to 140 years old but look about 90 years old (McCoy in TNG) then something must have happened in that universe for this to be the case.
Khan was a product of eugenics though wasn't he? Rather than genetics? Maybe he's actually a clone of Big Boss......