Many people choose not to take drugs for fear of health consequences. Although this may be a legitimate concern depending on the degree and duration of drug use, this is not the reason I chose to stay natural. In fact, I believe that the dangers of steroids and other performance enhancing drugs are probably exaggerated greatly and sensationalized by the media. In my opinion, scare tactics like, "You're going to get a brain tumor and liver cancer" aren't really accurate or effective. If this were an effective approach, then drug use wouldn't be so widespread today.
It's not a matter of morals, ethics or cheating either. How does one define "moral behavior?" I believe the only definition of moral behavior that most people will agree on is that "moral" means you never do anything to hurt another human being or infringe on their right to do what they want with their lives. As long as you're not hurting or infringing on others, then who's to judge what's right or wrong? Few people would disagree that it shows questionable morals and a lack of character to take drugs, lie about it and compete in a drug tested competition, but as long as everyone is on a level playing field, then morality is probably not a valid argument.
My prime motivation for staying natural is not a matter of right or wrong, healthy or unhealthy. My motivation is different: What I want is the joy and fulfillment that only comes from becoming the best I can be without using any artificial assistance. I want to fully express the possibilities of the human body, mind and spirit. I want to actualize my full potential. If I take drugs, then I won't really know what my true potential is; I'll never know whether it's the drugs or me.
The real joy in athletics or bodybuilding is not in having a beautiful body or a 1st place award; the joy is in earning it. The joy is in working hard and seeing the type of person you become in pursuit of your goals. The joy is in watching yourself become a real winner and a true champion - on the inside. Earning it makes you into a better human being. You develop character, integrity, persistence, determination and a strong work ethic - all positive qualities that transfer to other areas of your life. There's no true and lasting joy or fulfillment in results that are artificially produced. Using drugs is like going to the store and buying the trophy. There's no joy in that - you didn't earn that!
Suppose you took a "magic pill" and developed an incredible body in a very short period of time. Do you really think you're going to feel happy, proud and fulfilled? Do you think your self-esteem is going to increase? I don't think so. I think that despite the way you'd look on the outside, and despite some fleeting and superficial satisfaction, deep on the inside you'd feel that your "victory" was hollow. In the long run, I think your self-esteem would go down! Especially when your illusory gains quickly vanish as soon as your crutch is removed.