Yesterday the U.S. Court of Appeals for the 9th Circuit sided with federal investigators seeking to examine the supposedly anonymous and confidential results of drug tests taken by baseball players in 2003. Management assured the players that the tests were intended only to measure the prevalence of steroid use in Major League Baseball and that individual results would not be publicly revealed or become the basis for disciplinary action. The laboratories that performed the tests were supposed to destroy the samples and the records linking results to particular players, but the Justice Department used subpoenas to force the labs to preserve them for use in its investigation of illegal steroid distribution. Although U.S. district courts in San Francisco, Los Angeles, and Nevada ruled that using information from the tests violated the players' privacy rights, a 9th Circuit panel disagreed. The decision, which provoked a stong, 70-page dissent, does not seem to be available online yet, so I have not read it. But in addition to threatening the privacy of medical records, it seems likely to undermine scientific research that depends on assurances of confidentiality to elicit information. If subjects in studies of sensitive topics such as drug use, sex, and gambling know researchers' promises can be overridden by federal prosecutors, why should they agree to participate?