Gene doping may not be currently present at the Beijing Games, but anti-doping experts remain worried about the illegal use of gene therapy.

David Howman, director general of the World Anti-Doping Agency (WADA), voiced his concerns over the illegal practices Sunday.

"We worry about unfair practices. My concern is that somebody is trying to do it without having it medically verified and ethically confirmed.

"It is like manufacturing drugs without under proper scrutiny," he said.

The WADA director is overseeing the anti-doping program for the Games. His organization plays the role of independent observer for the program and carries out about 1,000 of the 4,500 tests during the Games. It also set up an anti-doping outreach program for athletes in the Olympic Village.

"We are doing a lot of work in gene therapy because we want it to be in place for public health reasons," he said.