By introducing proprietary, patent-protected, genetically engineered porcine organs into an organ transplant system, kidney xenotransplantation has the potential to alter many aspects of the system. While it is too soon to know for sure what the impact will be, we are cautious: patent-protected kidneys, like patent-protected pharmaceuticals, may be prohibitively expensive; some patients may not want to receive a pig organ; barriers to equitable access and distribution will remain; potential living donors may be discouraged if xenogeneic options are available; and the concept of ‘demand’ may change as the supply increases. Emilien Seizilles de Mazancourt believes that our arguments are unconvincing and that we should all be more optimistic. In this response, we defend our concern that implementing clinical xenotransplantation may not be the panacea it is hoped for.