Abstract

This paper queries why we are more reluctant to perform stem cell research on human than on nonhuman embryos, given their remarkable similarities together with the former's greater promise for addressing human illnesses. I begin by examining two leading arguments for prohibiting stem cell research on human embryos. The first type of argument suggests that we should not interfere with the potential for human life. This argument, advanced in different ways by both utilitarians and religious believers, inadequately grapples with the moral complexities raised by current technologies, such as IVF and cloning. Moreover, it fails to address the significant adverse effects of human overpopulation to both human and nonhuman well-being. The second line of argument addressed here suggests that we are morally prohibited from "playing God." This argument overlooks the various ways in which we do—indeed, we must—make life and death decisions. Further, the argument rests on an undefended assumption that we are only prohibited from making such decisions with regard to human life, while remaining free to make such decisions with regard to animals without apparent moral qualms. On the contrary, I argue that, from a fully ethical Darwinian standpoint, we must treat both human and nonhuman life with respect. Far from requiring us to abstain from difficult moral decision making, an attitude of respect toward all life requires human willingness to take responsibility for making difficult—indeed, sometimes excruciating—moral decisions