He doesn't take steroids.
He has been amazing people since he was a young teenager...contrary to popular belief, he didn't 'come from nowhere.'
I find it very sad that you can observe a feat so amazing and dismiss it, because of your preconceived ideas. 
2 points - first I did not say he took steroids. That is your preconceived idea about my statement. What I said was that I suspect he took performance enhancing drugs. He has never tested positive for a steroid (although having said that, there are periods of time when he trains pretty much in isolation in his home country, away from any testers, so in the past quite possibly may have been using a fast acting steroid with a short detection span).
But quite a part from steriods, there a range of other non-steroid performance enhancing substances he may have used (HGH being just one such example). Also possibly new forms of hard to detect EPO-like substances (which are usually used by middle to long distance runners, but which sprinters are now also using, especially in off-season training).
Secondly - I did not dismiss the feat. What he has done is amazing (whether with our without drugs makes no difference to me). I felt the same about Ben Johnson. So what if he tested positive. His run at the 1988 Olympics was incredible, and his positive test result does not make me "dismiss that feat" either.