With the Vancouver Olympics approaching, sports regulators are taking note of a new wave of genetic technologies that could one day be used to cheat.

Like steroids and other performance enhancers, "gene doping" might soon allow athletes to grow bigger, stronger, and faster via unnatural means.

(Related: "What It Takes to Build the Unbeatable Body" in National Geographic magazine.)

While nobody knows if gene doping is currently being practiced, "it can be done now," said Theodore Friedmann, a gene-therapy researcher at the University of California, San Diego.

Most likely, current efforts would be "hamfisted" and dangerous, he said. But "we know there are disreputable people in sport with access to technology and a lot of money."

Friedmann and colleagues are therefore calling on scientists to help keep gene doping out of the Olympics and other sports events. The experts advise controlling access to gene therapies and warning athletes of the potentially serious health risks.

"Marathon Mice"

No Vancouver Olympian has been accused of gene doping to date.

But Friedmann and colleagues note in tomorrow's issue of the journal Science that it's currently possible for athletes seeking to increase endurance to do so by boosting their muscle cells' expression of a gene called PPAR-∂. (Get an overview of human genetics.)

This gene affects muscle-cell metabolism, and "it also has major effects on fat metabolism and is one of the things being looked at for treatment of obesity and diabetes," Friedmann said.

When used in mice, PPAR-∂ converted ordinary creatures into superathletes, dubbed marathon mice.

Another potential gene-therapy agent is Repoxygen, a medication that was being considered as a way to fight anemia, Friedmann said.

The experimental technique boosts red blood cell production—which would be a way for athletes to increase the amount of oxygen delivered by blood to the muscles. In fact, in 2006 a German newspaper reported on a coach caught trying to buy Repoxygen, which is not approved for human use.

Misusing such treatments via gene doping is dangerous, Friedmann said, with substantial risks of cancer or even death.

How to Catch Olympics Cheats

Unlike drug enhancements, gene doping won't show up in existing blood or urine tests.

To catch gene dopers, sports authorities are considering new testing methods based on looking for changes in cheaters' gene expression and cellular proteins.

"Doping agents don't act in a vacuum," Friedmann said. "They have multiple effects, and many of these will influence the way in which genes are expressed and the proteins produced. If you look at all 25,000 [human] genes, there will be a large number of changes" after gene doping.

Figuring out which changes are caused by doping, however, won't be easy.

"The biggest problem would be understanding what other factors might affect the pattern," said Michael Lawton, molecular toxicologist and drug-safety expert at the pharmaceutical giant Pfizer.

Gender, age, diet, and exercise can all affect gene expression, he said. "What you want is to avoid false positives that you think are drug use but are actually something else."

Study author Friedmann agrees that looking for changes in gene expression isn't a validated and foolproof approach yet, but he thinks definitive tests will be coming down the line.

He also notes that, while delving into athletes' genomes raises important privacy issues, "that's kind of the cost of being an elite athlete."

Mari Holden, a silver-medal cyclist from the 2000 Summer Olympics and now a cycling coach, agrees.