Within a decade, most of today's synthetic performance-enhancing drugs—from anabolic steroids to erythropoietin (EPO)—may be all but abandoned in favor of a far more effective (and all but undetectable) strategy: gene doping.

"By 2010, drug testing will likely be a moot point," says Yesalis. "Viruses and bacteria—the same gene delivery systems we're using now in medicine—will be used to send genetic messages to an athlete's cells. You want larger deltoid muscles? You want quicker reaction time, or more red blood cells? You'll just turn on your insulin production, your natural amphetamine production, and your EPO production. The sky's the limit."

University of Chicago researchers have already enhanced the EPO-producing gene in mice and monkeys. Chiron, a California biotech firm, obtained similar results with baboons. Given the breakneck pace of genetic research, clinical trials of EPO therapy in humans could begin as early as 2003. If they're successful, a single injection of modified genes could radically increase endurance by boosting an athlete's red blood cell count by as much as 40 percent—for an entire season.

The EPO gene is just the tip of the iceberg. In 1998, scientists at the University College London Center for Cardiovascular Research discovered the so-called "jock gene," which regulates an enzyme that controls electrolytes and blood vessel size; a form of the gene is present in many mountaineers and endurance athletes. But truly top-flight competitors like, say, Shaquille O'Neal possess a blend of synergic qualities: in Shaq's case, dizzying height, strong knees, and exceptional hand-eye coordination. Such prodigies are born, not made, claims Yesalis. "The media like to pretend these athletes succeed by pure hard work. But I've coached high school kids who worked as hard, or harder, than many elite athletes. The truth is, they're genetically set to do that sport."

The Human Genome Project recently succeeded (years ahead of projections) in producing a nearly complete map of our genetic makeup. But reports that this milestone will be used only to treat disease are grossly naive, many sports physiologists believe. The time may come when biotech firms pay vast sums for the rights to sports heroes' genetic codes. Gene "cocktails," fabulously expensive, will deliver the hottest traits of celebrity athletes. Lose that cancer gene and Lance Armstrong Infusion will be a breakaway bestseller—right up there with Spitz Mix and Tiger Milk. And how much would a youth with hoop dreams beg, borrow, or steal for a genetic dose of Heir Jordan?