>>The World Anti-Doping Association (WADA) prohibits an athlete from using a substance that fulfills two of the following three criteria: 1) It is performance-enhancing; 2) It is harmful to health; 3) It runs counter to the spirit of the sport.

these things are extremely hard to quantify which is why there are explicit lists of "prohibited substances" where the line is drawn more or less arbitrarily. my personal opinion is with the exception of artificial hormones everything else should be allowed.

and when it does come to 'roids and hgh (which btw are demonized beyond any reason) - I like the way powerlifting federations address it - as an athlete you can compete in a tested (which still of course doesn't guarantee the athletes to be "clean") or "untested" federation where anything goes.