The International Olympic Committee (IOC) and WADA insist that they are doing all they can to ensure drugs do not sully the Beijing Games.
But gene therapy specialist Dr Theodore Friedmann from the University of California says organisers could be faced with some unfamiliar techniques as athletes experiment with genetic tampering.
Speaking in England he says gene doping can give a sporting advantage and even help the body produce substances that are already being used to cheat, like the endurance enhancing EPO.
"It is possible to introduce genes into people and change the DNA of some of their cells, genes that affect the way muscles function or the way that they heal after injury," he said.
Although gene doping is probably still in its infancy, as techniques become more sophisticated naturally occurring hormones could be boosted or altered to enhance performance.
"In mice and in monkeys and in other tests that have been...