We read with interest the recent article on criteria for patient selection of cardiac xenotransplantation by Kögel et al.1 The authors recognise the benefits and concerns of first developing xenotransplantation trials in children (or at least concurrent development). They conclude that, based on (1) the vulnerable nature of children and (2) the observation that ‘the benefits of cardiac xenotransplantation have never been systematically proven in humans,’ that the ‘very first clinical trials should be conducted with adult patients.’ This is a (...) long-standing contention in xenotransplantation that, to our knowledge, finds its origins in the Nuffield Council on Bioethics’ 1996 report on xenotransplantation, which states: ‘It would be difficult to justify the involvement of children in major and risky xenotransplantation trials before some of the uncertainties have been eliminated in trials involving adults.’2 However, given the cardiac allotransplant waitlist mortality borne by some paediatric patients, as well as other factors that raise unique candidacy considerations in children compared with adults—and arguably make some children better candidates than adults—we do not believe …. (shrink)