Research with Human Embryonic Stem Cells: Ethical Considerations

Article excerpt

On 5 November 1998 Geron Corporation announced that scientists working in collaboration with Geron had succeeded in establishing cell culture lines of human embryonic stem (hES) cells. Because these cells are considered pluripotent (capable of being the precursors to a variety of human cell types) and immortal (sustainable in culture and reproducing themselves indefinitely), they represent a major breakthrough in scientific research, with potential for significant advances in tissue transplantation, pharmaceutical testing, and embryology.

Prior to the November announcement, the Geron Ethics Advisory Board developed "A Statement on Human Embryonic Stem Cells"[1] as a set of guidelines for hES research. [See Box.] This essay provides an expansion and elaboration of the particular warrants and moral reasoning for that statement.

The EAB did not offer a carte blanche approval of research on hES cells undertaken by Geron or any other entity. The board unanimously affirmed that such research can be undertaken ethically, contingent upon meeting a range of qualifying conditions. The initial work of the board has been to specify such conditions; its continued work will consist of assessing Geron's developing research in light of them. Hence here we also include some preliminary reflections on ethical issues in human embryonic germ cell (hEG) research.

Moreover, the EAB perceived the need for and urged continued public discussion of the complex ethical issues emerging from such research. Thus the statement and this companion essay should be seen not only as an initial clarification of the EAB's own position, but also as an effort to contribute to and invite that public discourse. We enumerate some specific questions for further reflection at the end of this essay.

1. "The blastocyst must be treated with the respect appropriate to early human embryonic tissue."

The creation of hES cells involves isolation of cells from the blastocyst.[2] The blastocyst consists of an outer cellular layer, which would develop as the placenta, and an inner cell mass, which would develop as the body of the fetus. The outer layer is dissolved and the resulting mass of cells is used for research. Thus a central ethical issue is the moral status of the blastocyst.

To raise the matter of "moral status" is to ask, Does a given entity possess the requisite qualities or characteristics that entitle it to moral consideration and concern? "Moral status" thus functions as a threshold idea: entities with moral status should be treated in a manner differently from entities without that status. The EAB affirms that the blastocyst has moral status and hence should be treated with respect.[3]

What sort of moral status does the blastocyst have? This question has riveted political, religious, and ethical attention, and profound and substantial disagreement is based not only on contending biological interpretations but also on deeply held philosophical and theological considerations. Some have argued for conception as the relevant consideration, others for the development of the "primitive streak" (the precursor to the spinal cord of an individual fetus) as a defining moment, and some for utilizing implantation as the crucial threshold for moral status.[4]

Reviewing the complex literature on this topic, Ted Peters, following Daniel Callahan, distinguishes three basic schools of thought.[5] The genetic school locates the beginning of human personhood, and thus claims of moral status and dignity, at the genetic beginning--that is, at conception, at the point where one's individual genome is set. Here, a criterion for moral status (human genetic heritage) is linked to a particular point in human life (conception). The developmental school while granting that human life begins at conception, holds equally that human personhood--and hence full moral status-is a later development. Here, moral status is understood developmentally: as the conceptus develops from blastocyst to fetus and beyond so too does moral status grow (although proponents differ on when exactly the threshold of moral status is reached). …