It's not. Using a motor on your bicycle, a little propeller tied to your back while swimming, and a mechanically telescoping pole to vault with are also disallowed. So using mechanical assistance is also in the list of disallowed things. An unfortunate loss for the inventive sportsman.

Other disallowed things:

* having spectators strategically fall in the path of your competitors. Unfortunate for the cunning sportsman.

* adjusting the physical conditions of your part of the field (no ultra-bouncy start mat for when you are going to make the long jump). A pity, the inventive sportsman misses out again

* using a separate biological aid. No horses for the sprinter, or palanquins for the long distance runner, no team of people boosting you over the high jump bar. A tragic loss for the sportsman who can recruit nature's finest.

Just to be clear on what is considered doping, the WADA considers any substance (or method) to be on the prohibited list if it meets two of the following 3 criteria[1]:

- It has the potential to enhance or enhances sport performance - It represents an actual or potential health risk to the athlete - It violates the spirit of sport

So, in theory, the distinction of acceptable and non-acceptable is not drawn (only) in performance-enhancing drugs.

Another thing to consider is that (pre-BALCO) you are not always charged on taking performance-enhancing drugs but in either having some synthetic drugs on your organism detected or having some measurements over what is considered "normal" in humans. For example, T/E higher than 4:1 ratio. This means that the ratio Testosterone/Epitestosterone can be 4:1. If an athlete has a 1:1 level (which is normal), doping himself with testosterone won't be considered positive as long as it's kept below 4:1. All assuming that exogenous testosterone cannot be detected.

As far as I know, BALCO was the first time than some athletes were sanctioned without testing positive.

[1] http://www.usada.org/substances/prohibited-list/ [2] http://www.webmd.com/fitness-exercise/steroid-doping-questio...

Because we don't want a world in which athletes have to destroy their bodies in order to be competitive.

ETA: And let's be clear, that's exactly where it leads. People will feel compelled to start doping younger and younger, when they can do more and more damage to themselves (like giving themselves testicular cancer) -- young people also have poorer judgment about these things.

We've already seen all this happen.

I don't know a ton about this stuff, but:

Isn't it because things like steroids are dangerous and have serious adverse effects, and athletes shouldn't have to endanger themselves in that way, just to stay relevant.

There are thousands of rules in any sport, anti-doping is just on of them. Anyone trying to get around the rules is just cheating, so why should doping be excused?