Fans hold up a sign prior to a Major League Baseball game.

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"If I could give you a pill that would make you an Olympic champion -- and also kill you in a year -- would you take it?" Dr. Gabe Mirkin asked competitive runners that question in advance of a Washington, D.C., road race in 1967. Of the approximately 100 athletes who returned Mirkin's questionnaire, more than half responded that they would take the pill.

The prevalence of performance-enhancing drugs in sports has increased in the 43 years since Mirkin, a physician and sports medicine expert, handed out his survey. The desire to win is, naturally, ever present while, at the same time, new research and technologies have expanded the number of options for cheating your way onto the podium. For example, today's performance-enhancing drugs come in many forms other than a pill ("the cream and the clear," a testosterone-based ointment described by accused athletes in court testimony, comes to mind), but the results they produce are still highly sought after. Professional cycling has been repeatedly rocked by revelations and allegations of drug use. Every two years as the Olympic Games begin, we hear about athletes using or at least being tested for performance-enhancing drugs. Major League Baseball is still trying to repair its image from the steroid era. And the list goes on.

Some athletes get away with using drugs; others wind up suspended from their sport or even in jail, and still others die prematurely. It's a risky and complex game within a game that plays itself out on a public stage. In this article, we'll discuss why some athletes take drugs, what the major classes of drugs and their side effects are, and how people test for drug use.