Bioethics Forum Essay

ES Cells and iPS Cells: A Distinction with a Difference

Gregory Kaebnick recently suggested in Bioethics Forum that apparent differences between induced pluripotent stem (iPS) cells and embryos created by somatic cell nuclear transfer may not be all that relevant from a moral point of view. As Kaebnick explains, both techniques involve the reprogramming of somatic nuclei (either with the addition of gene transcription factors to somatic cells, which is what produces iPS cells, or with the help of egg cytoplasm, as in cloning). As well, both techniques ultimately may be capable of generating human life. On this view, those who object to cloning-based stem cell research as an instance of unjustified embryo killing should also object to the creation and use of iPS cells (which is a possible new kind of embryo). By the same token, those who are enthusiastic about iPS cells should endorse cloning-based stem cell research.

In response, Cynthia Cohen and Bruce Brandhorst argue that there are morally significant differences between iPS cells and cloned embryos. In their view, iPS cells are more akin to embryonic stem (ES) cells than to cloned embryos or any other kind of embryo for that matter. Cohen and Brandhorst compare iPS cells and ES cells and conclude that

[neither will] develop into newborn humans if transferred to the bodies of women for implantation because (1) they lack the extracellular layer required prior to implantation, (2) they are too small and lack the internal organization needed to function as zygotes, and (3) they are not totipotent. They can produce all the cells of the embryo proper when implanted into an embryo host, but not the extraembryonic tissues required for the development of the fetus. [Note, this conclusion is contested by Lee Silver in his commentary “More on iPS Cells.”]

In their view, though further research is needed to confirm that iPS cells can be as safe and effective as ES cells for cell therapy, there is good reason to be enthusiastic about iPS cells. This enthusiasm, however, should not undermine cloning-based ES cell research.

In short, Kaebnick suggests that iPS cells and cloned embryos may be the same in morally relevant respects, while Cohen and Brandhorst argue the opposite. What the two commentaries share, unfortunately, is a complete failure to appreciate the most important moral difference between stem cell research involving cell reprogramming of somatic nuclei and cloning-based stem-cell research. This is that they have a very different impact on women. Indeed, although Cohen and Brandhorst note that “concern about the fate of the eggs destroyed in somatic cell nuclear transfer has not been a significant feature of the objections to the production of ‘clonotes,’” they fail to remark that concern about the women who provide the eggs for somatic cell nuclear transfer has been a significant feature of the objections to cloning-based stem cell research.

Unlike research to create iPS cells, cloning-based stem cell research requires the use of human oocytes. Human oocytes come from women who undergo hormonal stimulation and surgical egg retrieval at considerable risk of harm to themselves. One of the more significant physical harms of superovulation is ovarian hyperstimulation syndrome, which can involve nausea, vomiting, diarrhea, and respiratory difficulty, and at its most severe can produce life-threatening complications. In addition, when the women who provide eggs are also infertility patients, they may experience psychological harms when they do not become pregnant during an IVF cycle in which some of their eggs were given up or sold for research. There are the potential harms of coercion and exploitation of women and the more general harm of commodification of both reproductive tissues and reproductive labor.

As far as I can tell, the creation of iPS cells for regenerative medicine does not visit physical or psychological harms on women, involves no coercion or exploitation of women, and does not contribute to the commodification of reproductive labor and tissue. If I am right, then setting aside the question of moral status, these facts alone provide us with sound moral reasons to prefer research aimed at creating iPS cell to research involving the creation and destruction of cloned human embryos for stem cell research.

Françoise Baylis is Professor and Canada Research Chair in Bioethics and Philosophy at Dalhousie University, Canada. The author is a member of the board of directors of Assisted Human Reproduction Canada. The views expressed herein are her own.


Readers respond

Ms. Baylis is absolutely correct in her assertion that, even without moral considerations, the problematic issue of women’s health and safety should be enough justification to deter the continued quest for harvesting oocytes for cloning research. Despite this, recent discussions arising in the Medical and Ethical Standards Working Group of the California Institute for Regenerative Medicine suggest that rather than taking this course, ways of maneuvering around California’s law prohibiting compensation for egg procurement are being presented as legally possible. Questions arise regarding the push to continue cloning research when alternatives are being presented, which could eliminate the risks to women’s health ( including long term risks which are not being studied). Why aren’t they being addressed?

– Debra Greenfield J.D.,
Pro-Choice Alliance for Responsible Research


In our brief note, “Getting Clear on the Ethics of iPS Cells,” we discussed Kaebnick’s proposal that induced pluripotent stem (iPS) cells are akin to the “clonotes” that result from somatic cell nuclear transfer, since both involve reprogramming the nucleus of a human somatic cell. For a discussion of the issue that Baylis raises, the impact on women of the search for eggs for somatic cell nuclear transfer, see C.B. Cohen, “Ethical Issues in Embryonic Stem Cell research,” Journal of the American Medical Association 285, no. 11 (2001): 1439.

– Cynthia B. Cohen, Ph.D., J.D.
Georgetown University

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