For years, the World Anti-Doping Agency has considered requiring all Olympic athletes to submit copies of their genetic code. It would work as a check on so-called "gene doping," the idea of changing the body’s biological machinery to make it stronger, run faster, or recover more quickly. A clean slate would reveal any nefarious performance-boosting tweaks—like, theoretically, altering the expression of fast-twitch muscle genes to engineer a perfect sprinter.

Establishing a genetic baseline for every professional athlete has long been cost-prohibitive—especially if it calls for a full genome sequence. But on Monday, February 5, the proposal is being seriously discussed for the first time today at WADA's headquarters in Montreal. As the cost of sequencing a person’s entire genome drops to only a few hundred dollars, the agency could implement the plan within the next few years. “It will be easy in the future to have full genome sequencing for a reasonable amount of money,” said Olivier Rabin, WADA’s science director. “It will be reasonable to have full genome sequencing with some very strong ethical guidelines.”

Genetic sequencing would be an extension of an idea sports authorities developed in 2008, called the biological passport. It serves as a way of monitoring various indicators of an athlete’s blood, hormones, and body chemistry over time—looking for changes that could indicate cheating, even though the athlete may not have triggered a positive drug test. The passport looks for physiological changes caused by doping. And it has an eight-year statute of limitations so they can re-test older blood or urine samples when new tests or analytical methods are developed.

WADA authorities have already used the passport to catch athletes who use trace amounts of drugs that are below the testing threshold. But without a baseline read of an athlete's genes, it would be harder to identify doping cases that modify the body's blueprint itself. WADA has already banned gene doping—the practice of manipulating the genetic code to boost athletic performance—in anticipation of new forms of cheating, though no athletes have been charged so far. In 2006, a German track coach was suspected of using an anemia drug called Repoxygen to help turn on genes that control the production of blood oxygen levels. While he didn't get busted for that offense, he was later convicted of giving performance-enhancing drugs to teen athletes.

Sports scientists who are advising WADA now are considering if the best way to prevent gene doping would be to have a record of the athlete’s entire genetic code—or possibly, just the sections that contain genes associated with athletic performance.

The problem is that genes often work in combination with each other in ways that aren’t completely understood, according to Theodore Friedmann, head of WADA’s gene doping advisory panel and a professor of pediatrics at the University of California San Diego. “The connection between a given gene and a given athletic ability is not one to one,” Friedmann says. “People have claimed that specific genes for fast-twitch muscle fibers or energy metabolism will influence athletic potential, and I think there's probably some truth in those. But they are not specific determinants to whether they are a successful athlete or not.”

Gene-editing techniques such as Crispr/Cas-9 could theoretically be used to inhibit genes regulating myostatin, a growth factor that inhibits muscle development. Several young children have been reported with myostatin abnormalities, and have developed enormous muscles. And these same gene-editing techniques could be use to insert genes that regulate blood-oxygen levels, for example, which are critical for endurance athletes, or genes that regulate removal of lactic acid after a hard effort. But Friedmann, who runs a gene therapy lab at UCSD, is skeptical that genetically-enhanced super-athletes will be trotting around Olympic stadiums anytime soon.