The principal question of this literature review is: do the advantages of stem cell research justify any unethical or unmoral practices used in stem cell research? The following five working thesis statements have been constructed for discussion.
Embryos are non-viable before implantation
In human embryonic stem cell (hES) research, blastocyst’s inner cell mass is taken out and grown to create stem cells, which are then stimulated to differentiate to desirous tissue. Bioethicists and religious people always argued about the living nature of the embryo and fetus, comparing it with the individualistic human entity. The human embryo enjoys dignity, and using it for research may decrease the respect for human life. According to Cogle et al., “there is substantial debate regarding at which specific stage dignity is conferred in development (conception, primitive streak development, implantation, “quickening,” or birth” (999). The authors viewed moral and legal status as being worthy of human rights only after the embryo is implanted in the uterus. Blastocysts developed after 4 days of fertilization and before implantation has a homogeneous population of inner cell mass which is said to be non-viable and are suitable hES source.
The authors listed a number of therapeutic applications, particularly regeneration of damaged organs like heart muscle, brain pancreatic islet cells, etc. H-W Denker, however, believed that there is cryptic spatial information about cell differentiation and embryonic pattern formation within the inner cell mass (667). Being a pre-embryo, even though not implanted, these cells are also protected by the same right as a developed embryo. Further, in animal models, blastocyst cells form an embryoid body resembling a true embryo. Thus ethically, the cells are very much similar to the embryo. When implanted at extra-uterine sites, inner cell mass grows with the chaotic arrangement, apparently suggesting its inability to differentiate. However, upon placing back to the uterus, normal embryonic growth is resumed, which means the cells indeed are “living beings.” From the author’s point of view, morulae, a 60-70 cell mass stage prior to blastocyst, are considered totipotent, which means each cell can develop into a complete individual. As the cells are not programmed to differentiate, they are considered non-viable and are ethically usable for research. The same argument was given by Kristina Hug, who went a step ahead and proposed that one totipotent cell can be grown as hES without damaging the morulae, which can eventually be replanted for normal embryo development (1008), hence practically no damage to the fetus.
Therapeutic cloning for human disease cure is unethical
Transplantation with hES may lead to rejection, just like grafts. Somatic cell nuclear transfer (SCNT) to anucleated eggs collected from in vitro fertilization clinics may generate another class of stem cells. These cells can replicate to genetically identical offspring by “reproductive cloning” like Dolly was cloned. Alternatively, the cells are prepared to produce any tissue of the body, which can rejuvenate the damaged tissue of the patient by replacing them (“therapeutic cloning”). The latter, according to Cogle et al., has immense potential to cure Parkinson’s, Alzheimer’s, Rheumatic Arthritis, diabetes mellitus, etc. The same authors, however, cautioned about consequent abnormalities like arthritis, atypical joint distribution, and lung cancer resulting in early deaths in cloned animals (995).
Another concern, as quoted, was “potential for eugenics; the selection of healthier genetic traits potentially leading to the commercialization of human procreation.” Hug advocated for therapeutic cloning despite problems by making an analogy “assassinating Hitler might have saved 6 million Jewish people. Similarly, sacrificing human embryos for research might lead to finding a cure for millions of suffering patients.” In counter-argument, Hug added “If all the technical problems in the first steps of cell nuclear replacement techniques are solved successfully, then it would become both easier and more tempting (because certain risks have been reduced) to try to use nuclear replacement techniques for reproductive cloning” (1005-06). The first SCNT human trial in South Korea by W.S. Hwang was an utter failure and had raised several ethical questions, most prominent being, stimulated egg production as an undercover and by medically unsound methods, and later not compensating for the consequent health problems in the donors (Steinbrook 324-26).
Dispense the “spare and low-grade” embryos rather than choose for research
Embryos that are left in fertilization clinics in the frozen state are considered as “spare.” Embryos are also graded base on quality from low- to high grades. The low-grade ones are not suitable for the implant as this may lead to abortion, gestation problems, or inborn defects. A question was asked whether research with such embryos means a lack of respect for human life. Arguments broadly discounted this notion (Hug 1003), though cautioned about the possibility of dehumanizing practices like embryo farms, cloned babies, and the use of fetuses as spare parts and commoditization of human life. Further, this commercial pressure may lead to the exploitation of women. According to the author, a large number of unused eggs would be required for “therapeutic cloning,” thus putting pressure on the woman to donate eggs. Procurement of ova for the non-reproductive purpose would affect women’s status in society and might promote illegal trafficking of eggs from developing countries where the laws are not stringent.
This apprehension was strengthened by Hwang’s unethical research, in which egg retrieval was done in extremely harsh conditions, potentially damaging the modesty and health of volunteered donors (Steinbrook 324-26). For counter-argument sake (Hug 1003), “the embryos are anyway going to be destroyed (perished or defrosted) and if it is immoral to sacrifice them for treating infertility then why not to use them for saving a human life”? Another option is to declare low-grade embryos unfit for fertilization and use. It is immoral and grossly unethical to fertilize a woman fertile with defective embryos. According to Philip H. Schwartz, the donation of low-grade embryos is analog to the ethically and morally acceptable practice of donation of vital organs from “brain-dead” individuals. In both situations, the “human being (patient or the embryo)” is neurologically compromised (772-73). Embryos used for fertility are reared in a medium that is not the same as the one used for stem cell research (here, tissue development rather than embryonic development is the aim). Low-grade embryos perform equally well in the later medium. So far as the therapeutic application is concerned, the author cautioned, “it is difficult to assert whether or not embryonic stem cells harvested from high-grade versus low-grade embryos would be of equal quality with regard to their potential research or clinical applications” (Schwartz 774).
Donor’s consent and untimely withdrawal of consent at the cost of research
The authority seeking consent from the donor in normal circumstances has to be the clinician from a fertility clinic. Caulfield, Ogbogu, and Isasi, however, argued that the physician might influence the donor in favor of non-reproductive donation (1723). Whatever the situation could be, the donor has a right to know the purpose for which the egg is donated. Like organ donation, the donor retains the right to withdraw the consent for medical procedures or research trials. While the right in most cases is for an unlimited period, the authors claimed that this right should limit to a time before stem cell is created. If later, then researchers would face profound problems as cells are already being used in many laboratories, and material destruction would incur an enormous financial loss. Thus legally embryo is a different entity from gametes or the embryo donor. Another crucial issue raised was the anonymity of research and the whereabouts of the stem cells. In this situation, withdrawal of consent will not be possible at all. What if the cell lines are used for clinical trials, and there is no access to the health status of the donor? The patients may get unhealthy cells, which may aggravate the problem rather than solving it.
Creation of a hybrid of humans and animals is an unnatural practice
One of the options in SCNT is to transfer the nucleus to the de-nucleated egg of some other species (chimera) (Hug 1007). As opposed to most of the current guidelines, such options may lead to the creation of nonhuman animals. The use of such stem cells to regenerate human tissue needs advanced research in comparative animal models. Transplantation of human blood stem cells and skin grafts in mice has opened this avenue (Karpowicz, Cohen, and Kooy 331). Based on some early evidence, human retinal stem cells are being attempted to grow in the eye and brains of fetal monkeys. The results would prove whether human cells can functionally integrate with the developing primate retina. As argued by most ethicists, the basic concerns with such hypothetical experiments are a wrongful violation of nature, contravention of human moral taboos, violation of species integrity, and undermining respect and dignity of human beings. Nevertheless, the authors defended this action stating that inter-species cross-breeding of animals is not unnatural. Former taboos like blood transfusion, organ donation, homosexuality, etc., are now accepted and have become ethical and civic responsibility. Most classification schemes assigning species status are based on subjective criteria and are empirical and pragmatic, so where is the threat to species integrity? So far as dignity towards human beings is concerned, a mouse carrying a human-like ear (Karpowicz, Cohen, and Kooy 333) is undignified, but what if it were a rabbit-like ear? For experiments, human components (antigens, etc.) are transferred to animals, and then what difference to dignity it means if stem cells are implanted? Let us consider existing sheep/goat blastocyst and quail/chick embryonic chimeras. A human/chimpanzee chimera with nuclear programming may develop more human-type tissue with more human-like characteristics.
References
Caulfield, Timothy, Ubaka Ogbogu, and Rosario M. Isasi. “Informed consent in embryonic stem cell research: Are we following basic principles?” Canadian Medical Association Journal 176, 12 (2007): 1722-1725.
Cogle, Christopher R., Steven M. Guthrie, Ronald C. Sanders, William L. Allen, Edward W. Scott, and Bryon E. Peterson. “An overview of stem cell research and regulatory issues.” Mayo Clinical Proceedings 78 (2003): 993-1003.
Denker, H-W. “Potentiality of embryonic stem cells: an ethical problem even with alternative stem cell sources.” Journal of Medical Ethics 32 (2006): 665-671.
Hug, Kristina. “Sources of human embryos for stem cell research: ethical problems and their possible solutions. Medicina (Kaunas) 41 (2005): 1002-1010.
Karpowicz, Philip, Cynthia B. Cohen, and Derek van der Kooy. “It is ethical to transplant human stem cells into nonhuman embryos.” Nature Medicine 10.4 (2004): 331-335.
Schwartz, Philip H. “An approach to the ethical donation of human embryos for harvest of stem cells.” Reproductive BioMedicine 12 (2006): 771–775.
Steinbrook, R. “Egg donation and human embryonic stem-cell research.” The New England Journal of Medicine 354 (2006): 324-326.