Two Harvard University researchers call for a moratorium on clinical trials of xenotransplantation in a brief Nature commentary. They specifically invoke the precedent of Asilomar as a “turning point” for scientists’ approach to public responsibility. They suggest that the decisions of whether and how to proceed with such clinical trials should not be left to technical experts alone, instead requiring “an informed public debate.” They identify a single chief risk of xenotransplantation research: the potential of a pathogen to cross the species barrier.