The Vulture and Stem Cells

Abstract

Rosenthal (July 17 issue)¹ begins her article by considering the myth of Prometheus. She says that a vulture preyed daily on his self-renewing liver. Indeed, Greek mythology tells us that a bird ate Prometheus's liver, but older sources allude to an eagle instead of a vulture^2,3 ( Figure 1 ). This is not a trivial point, because vultures are scavengers, whereas eagles are birds of prey. Vultures would never eat living animals. This cultural imprecision might seem unimportant, but terminology is key with respect to the issue of the “stem-cell promise.” Semantic differences between terms such as “nuclear transfer” and “therapeutic cloning”are very important.