The first clinical trial transplanting gene-edited pig kidneys into humans could start this year. They raise important ethical issues.

The realized promise of xenotransplantation seems to be quickly approaching, following the medical breakthrough of a pig kidney functioning for a record two months in a deceased human body. This milestone has received overwhelmingly positive media attention. Ethicists, physicians, and transplantation specialists have shared their apprehensions about the risks of implanting animal-grown organs into humans. However, conspicuously absent from these discussions is a major stakeholder: the animals.

. A report last week in the New York Times of a pig heart transplant performed at the University of Maryland Medical Center exemplifies a common myopic view of xenotransplantation research.

News of the first transplant of a pig’s heart into a human raises hope that the procedure could one day help alleviate the shortage of organs. But before we forge ahead with xenotransplantation trials, we should be concerned about several issues: the potential to spread pathogens, exploitation of human research participants, and animal welfare.

A remarkable experiment raises anew questions about whether brain-death is really death.