This issue of the Journal of Medical Ethics focusses on the ethical implications of recent scientific and medical advances: for humans, for animals and for the boundary between the two. In this month’s ‘Current controversy’, Julian Savulescu and Tsutomu Sawai consider the implications of recent research to transplant human brain organoids into the brains of infant rats, arguing that such technology has the potential to enhance the cognitive capacities of animals in ways which invites questions over their moral status.1 This (...) debate will only increase in intensity as more sophisticated brain organoids begin to be introduced, in the future, even, perhaps, to primates. The ‘Feature Article’, written by Rodger et al,2 and its commentaries similarly consider the ethical duties owed to animals in the conduct of medical research and treatment, although in the context of xenotransplantation, where organs from animals (in particular, pigs) are transplanted into humans in a bid to tackle organ shortages. While Rodger et al proposes that in order to be ethically defensible, xenotransplantation should use genetic ‘disenhancement’ so as to eliminate or minimise the pain and suffering experienced by animals, the commentaries raise a number of issues with this proposal, questioning whether this requires the author to accept the morally permissibility of xenotransplantation in the first place, as well as whether disenhancement might inadvertently discourage the development of more ethical ways to tackle organ shortages. Taken together, these papers raise significant questions, not just about …. (shrink)