The ethics of human embryos and embryonic stem cell research

The science of human embryonic stem (hES) cells holds tremendous promise for the discovery of revolutionary cellular therapeutic options for the restoration and regeneration of damaged or destroyed cells and tissues, and thus the treatment or even cure for a host of diseases and disabilities. Yet the fact that the derivation of hES cells from embryos normally results in their destruction poses ethical challenges, which for some, amounts to a veritable impasse to the further development of stem cell science. In this paper, we review the scientific and ethics literature on hES cells including the use of somatic cell nuclear transfer to generate cloned hES cells for biomedical research and potential clinical applications. The paper reviews the various normative theories on the moral status of the human embryo that capture issues ranging from the continuity of embryonic development to cognitive prerequisites for personhood such as sentience, rationality and self-awareness. We also discuss arguments for the symbolic value of human embryos and the need to respect the dignity of human embryos as potential persons. Beyond issues related to the destruction of human embryos, a number of other ethical issues germane to embryonic stem cell science are also considered such as the instrumentalization and commercialization of human materials for stem cell research, and the potential social and health risks to women in obtaining and donating oocytes or embryos for hES cell research. Finally, ethical questions arising from the relatively recent development of scientific methods to create new types of embryos for harvesting hES cells are also discussed.