What are the dangers of training in elite sports? In order to compete, athletes must go through rigorous training that does have harmful impacts on the competitor. Not only that we see the dangers of playing football, one of which is decreased longevity. I have yet to see a credible study regarding the dangers of performance enhancing drugs. That is the dangers with the use of the latter outweighing the non-use.
There is even performance enhancing drugs used in science by scientists:
http://www.webmd.com/brain/news/20080409/poll-scientists-use-brain-boosting-drugs
Banning these drugs or penalizing others for their use is, to me, backwards. No-one has an unfair advantage if everyone is utilizing the drug. They all are just about "equal" (not in the strictest of sense as naturally, some are better than others which means even if they all took drugs, it would be the same footing).
There are talks about testing students for drugs because there seems to be higher usage of adderall among students. But, in regards to the link above, if one wins a nobel prize because s/he confessed to taking performance enhancing drugs, are we going to take that nobel prize away?