Given the increasing need for solid organ and tissue transplants and the decreasing supply of suitable allographic organs and tissue to meet this need, it is understandable that the hope for successful xenotransplantation has resurfaced in recent years. The biomedical obstacles to xenotransplantation encountered in previous attempts could be mitigated or overcome by developments in immunosuppression and especially by genetic manipulation of organ source animals. In this essay we consider the history of xenotransplantation, discuss the biomedical obstacles to success, explore recent developments in transgenic sourcing of organs and tissues, and analyze the problem of infectious disease resulting from xenotransplantation (xenosis). We then apply a model of risk analysis to these risks. The conclusions of this risk analysis are used in an ethical evaluation of informed consent in xenotransplantation, with an ethical foundation in Kantian autonomy and Levinasian heteronomic alterity. Our conclusion is that individual and collective informed consent to the infectious disease risks of xenotransplantation requires an open, participatory and dialogical public policy process not yet seen in the United States and Europe. Until that process is created, we propose caution in xenotransplantation in general and a postponement of solid organ xenotransplants in particular.