A Swedish researcher said some men are missing testosterone-metabolizing genes that are key to the accuracy of athlete drug tests.

A study of 55 men injected with testosterone found that 17 of them later tested negative in doping tests, The New York Times reported Wednesday.

Molecular scientist Jenny Jakobsson Schulze of Karolinska University Hospital in Stockholm said about two-thirds of Asian men are missing both copies of the gene, compared to about 10 percent of Caucasians, the newspaper said.

The findings were published in The Journal of Clinical Endocrinology and Metabolism.

Dr. Don Catlin, the chief executive of the U.S.-based Anti-Doping Research group, said the findings are disturbing. "Basically, you have a license to cheat," he told the newspaper.

Copyright 2008 by United Press International