Kirk Johnson

About the author: Kirk Johnson is a writer for the New York Times.

The substance androstenedione, a compound that can temporarily boost levels of the hormone testosterone, became famous when baseball player and home run slugger Mark McGwire admitted using it during the 1998 baseball season. McGwire's admission epitomizes how performance drugs in sports have become a matter of public knowledge and debate. Changes in federal law regulating food supplements have made androstenedione and similar substances readily and legally obtainable in the United States. But many people wonder whether using these substances is a way of cheating, and whether there should be more legal or ethical restrictions on using such substances.

Mark McGwire, the brawny St. Louis Cardinals first baseman, has become a folk hero to many people for his skill...