Science - To publish or not to publish, that is not the question—or at least not the ultimate one. For the last few months, scientists, policymakers, and the public have intensely debated whether journals should reveal details of experiments by two labs that have engineered H5N1 avian influenza viruses that easily transmit among mammals—and could thus potentially spark a human flu pandemic. But there’s another difficult quandary in this tug of war between scientific freedom and bioterror fears. Both research teams relied on experiments with ferrets. How concerned should people be that what happened in Mustela putorius furo with these mutant viruses will apply to humans?