US Senator Tom Coburn is single-handedly blocking the passage of a bill through the Senate that aims to protect people from genetic discrimination.

Coburn (Republican, Oklahoma) is using a legislative tactic called a hold to block a Senate vote on the Genetic Information Nondiscrimination Act (GINA), which was passed in April by the House of Representatives on a vote of 420 to 3 (see Nature 447, 14–15; 2007). The bill would make it illegal for employers or insurers to use genetic information in hiring, firing, promotion or insurance-coverage decisions. President George W. Bush has promised to sign the bill into law should it reach his desk.

“I believe the bill, as drafted, contains unintended consequences,” Coburn wrote in a 1 August letter to his constituents, who have since deluged his office with complaining letters, e-mails and phone calls. “Congress has both the moral and legal responsibility to pay attention to details and get them right. I want to assure you that my hold on GINA is not because I oppose the bill's purpose, but because I am concerned about its lack of precision.”

The goalposts keep moving.

Coburn, who has holds on 87 bills, voted for essentially the same bill when the Senate passed it unanimously in 2005. At that time, both the House and Senate were controlled by Republicans, but the House refused to bring the bill to a vote. With Democrats now in charge of both, the bill is just one senator away from becoming law.

Coburn wants changes in the bill that would make it harder for victims to sue employers in some cases. He also says that the bill's definition of genetic tests isn't identical in the sections dealing with employers and insurers.

But its advocates dismiss these concerns as manufactured excuses. “The goalposts keep moving,” says Kathy Hudson, director of the Genetics and Public Policy Center at Johns Hopkins University in Baltimore, Maryland. “He raises a concern and that concern gets addressed or negated and all of a sudden there is a new concern.”