The transplantation of porcine organs to humans could in the future be a solution to the worldwide organ shortage, but is to date still highly experimental. Further research on the potential effects of crossing the species barrier is essential before clinical application is acceptable. However, many crucial questions on efficacy and safety will ultimately only be answered by well designed and controlled solid organ xenotransplantation trials on humans. This paper is concerned with the question under which conditions, given the risks involved and the ethical issues raised, such clinical trials should be resumed. An alternative means of overcoming the safety and ethical issues is suggested: willed body donation for scientific research in the case of permanent vegetative status. This paper argues that conducting trials on such bodies with prior consent is preferable to the use of human subjects without lack of brain function.