Albany Medical Center
May 28, 2013 | Posted By Zubin Master, PhD

For Part I of this blog, I will highlight a new discovery where scientists have now been able to create cloned stem cells and I will review two ethical debates that were central to earlier discourse surrounding stem cell research: (1) the moral status of human embryos and (2) the potential physical and social harms to women as egg providers.

So finally research cloning (a.k.a. therapeutic cloning) has been achieved! The technique is called somatic cell nuclear transfer (SCNT) and now has been used to derive human embryonic stem cells (hESCs) (Tachibana et al., Cell 2013). Performing SCNT using human oocytes is an astonishing accomplishment and has significant ethical and clinical implications.

Although the process Tachibana and colleagues used differed, typically SCNT involves taking a human ovum, removing its nuclear genetic material (a process known as enucleation), and replacing it with a diploid nucleus from any cell (i.e., the nucleus of an epithelial cell) and then parthenogenically activating the egg to initiate embryonic development. If this embryo was allowed to develop in vitro and was then transferred into a surrogate woman, the child born would be a clone of the individual who donated the somatic cell nucleus. This technique is commonly referred to as reproductive cloning and is banned in every nation that has policies on human cloning. This is the technique used to clone Dolly and many other animals. Therapeutic cloning differs in that instead of transferring the cloned embryo into a surrogate woman, cells can be isolated from the inner cell mass of blastocysts which will become hESCs. (See Cloning for Therapy Figure). The interest in cloning for many scientists, patients and others rests in creating cloned hESC cells for regenerative medicine because hESCs can differentiate into every cell of the adult body. SCNT was originally explained as a technique necessary to derive hESCs that are a clonal match to a patient so that when transplanted, the cells would be recognized as self and would not be immune rejected post-transplantation. Policies on therapeutic or research cloning differ from country to country and some permit it while others prohibit the practice. The scientific feat of research cloning was said to have been first done by Woo-Suk Hwang of South Korea, but his work was soon after proven to be fraudulent. Thus therapeutic cloning is scientifically and potentially clinically valuable. But there are tons of ethical issues surrounding research cloning.

Among the various ethical debates on stem cell research, a few have received as much attention as the moral status of human embryos. The idea was that if embryos are considered persons who are afforded inalienable rights (e.g., the right to life), they cannot be used to derive hESCs as this results in their destruction. In contrast, if human embryos do not have personhood and lack full moral status, it would be considered ethically permissible to use them to derive hESCs. Without getting into too much moral philosophy or biological development, some people believe that a human embryo has full moral status equivalent to persons at the moment of conception and thus creating hESCs, which results in its destruction, violates its right to life. But not everyone believes a human embryo is a person at the moment of conception. Some believe that human embryonic day 14 is morally and biologically significant because natural twinning cannot occur after this point and each twin is a person. It is for this reason that many religious doctrines consider embryonic day 14 as the moment an embryo becomes a person. Yet what is the biological and moral significance of conception or any discrete time point in the continuous developmental process? Others believe the theory that a human embryo deserves moral protection not because it has full moral status during a discrete developmental moment, but because it has the potential to become a full member of the moral community and have a life like ours. Human beings have values and interests and because an embryo will come to have these attributes, then we should grant it moral protection even during its earliest stages of development. But this theory too has issues. If an entity doesn’t have full moral status we are not morally obligated to offer it any protection, irrespective of its potentiality. Another belief is that for full moral status, entities are required to have several advanced cognitive capacities including consciousness and sentience. This view too lends to some troubling outcomes because it prevents infants, the elderly senile or incapacitated individuals from moral protections. In addition, some animals would have moral status equivalent to persons and thus deserve protection and this would likely affect how we conduct animal research and farming. A final theory I would like to mention is that of respecting human embryos. Here, we offer respect to human embryos because they are a salient symbol of human life. How we treat embryos reflects how we look at life more generally. We respect and do not burn the U.S. flag or deface artwork not because they have moral status, but because they are morally valuable and should be respected. Similarly, human embryos may not have full moral status but are deserving of respect. Based on this theory, many would permit the destruction of human embryos for stem cell research as it is a laudable goal, but probably won’t permit using embryos to make jewelry or for cosmetic testing. There are issues with all of these views and for the sake of brevity I will not delve into them any further here. A second major issue that received far less attention than discourse surrounding the moral status of embryos was the potential harms to women. Here, young fecund women can be solicited for their eggs in unregulated markets. Especially those in financial need may assume the risks ovarian stimulation and oocyte retrieval for payment. Yet whether it is unethical to offer a woman, even one in financial need, money for her eggs is still contested.


0 comments | Topics: Cloning, Reproductive Medicine, Stem Cell Research, Women's Reproductive Rights

Add A Comment
(it will not be displayed)
