I have followed the steroid story quite closely for a while now, even read Game of Shadows and a couple other books on the subject.
Tom mentioned Amphetamines being sort of a "gateway" to the stronger stuff like 'roids and what not.
We all know the story about McGwire and his "Andro."
A large problem with this issue is defining what a legal performance enhancer is and what isn't. Major league baseball teams shove Creatine down their players throats because they know it makes athletes bigger and faster.
I pop a couple advil before playing hoops with the boys, not because it helps my performance, but because it helps my weary bones not hurt so badly afterwards.
With so many supplements out there promising to make you skinnier, increase sexual performance, etc etc etc......it become a very slippery slope defining what is acceptable and therefore legal, and what is not.
Victor Conte and the BALCO crew were bona fide architects of athletes, in a twisted sort of way. The Cream and the Clear buffaloed testing officials for years, it was revolutionary stuff. I'd say odds are fifty fifty both Pujols and A Rod are on something "designer" to this day, it's just undectable...for now.
Whenever the stakes are high, someone will be angling for an advantage.
Be it Steroids, HGH, uppers, cocaine, Andro, Advil, Creatine, Ibuprofen or Ben Gay. It's so difficult to draw the line, IMHO.