Revisiting Inexorable Moral Confusion About the Moral Status of Human–Nonhuman Chimeras

In “Crossing Species Boundaries” (Robert and Baylis 2003), the authors explored the history, ethics, and prospective future of stem cell research involving chimeras made in part from human cells. They dismissed the various then-extant ethical objections to the creation of such chimeras, finding them all inadequate. In their stead, they sketched (but did not elaborate or defend) an alternative response—namely, that their creation would create a kind of inexorable moral confusion. Since then, a variety of alternative objections to—as well as justifications for—this research have emerged, alongside advances in the technologies for introducing genetic and cellular material across putative species boundaries. In this chapter, the authors revisit the notion of inexorable moral confusion, further specifying and elaborating the original concept in light of recent scientific and technical developments and ethical insights.