The debate over stem cell research is largely centered on human embryonic stem cells. These are cells taken from the inner mass of a blastocyst, usually in the first five to seven days following fertilization. These cells are called pluripotent because they have the potential to develop into any of the body's specialized cell types. The debate hinges on the value of the blastocyst as a potential human, balanced against the value of the therapies that are being developed by this research. An investigator is obliged to make every effort to protect the subjects of his research from harm. In the case of embryonic stem cells, removal of the pluripotent cells will usually end the viability of that embryo.
The gains already realized from stem cell research are promising, offering hope to millions who were previously hopeless. Twenty-five years of active research using blood stem cells has lead to successful treatments for blood disorders including cancer (Zerhouni, 2008). Stem cells have been coaxed into heart muscle cells, lung epithelial cells, and even nerve fiber cells (Landis, 2007). This research is invaluable to those suffering and it represents our current best hope for diseases that have lacked effective treatments. Currently, U.S. researchers have developed an efficient technique to derive dopamine-producing nerve cells from embryonic stem cells, the early tests have shown relief for Parkinson's-related movement problems (Landis, 2007).
Human embryonic stem cells can multiply without specialization (self-renew) or they can differentiate into a specific cell type (Zerhouni, 2008). Stem cells are difficult to harness and grow. They have been derived from both embryonic and non-embryonic sources, and theses cell types have different properties. These range of properties have made some cell lines especially useful for research purposes. However, to ensure reliability of results, multiple lines are needed for experimentation (Cohen et al., 2008).
The major source of new human embryonic stem cell lines internationally has been from embryos that remain following a completed in vitro fertilization (IVF) cycle. Generally, about half of the embryos produced for assisted reproduction are of low morphological quality. These are frequently donated for research. Other frequently donated embryos include those discarded because of the results of a pre-implantation genetic test, and those that have been frozen but are no longer needed (Cohen et al., 2008).
There are also a number of developing alternative stem cell technologies which could offer a potential solution to the ethical dilemmas surrounding embryonic stem cell research. Induced pluripotent cells from adult skin cells and amniotic fluid stem cells are among many possibilities. Stem cells from these sources have not yielded all of the essential characteristics of embryonic stem cells, and these technologies were developed through research done on embryonic stem cells (Landis, 2007). For these reasons, it is essential that researchers pursue all types of stem cells to develop the best possible therapies.
Critics of stem cell research have valid concerns: many worry that it offers a slippery slope of dehumanizing practices, such as embryo farms, human cloning, and the commodification of human life. Many also worry that the sanctity of life is being violated by the destruction of human embryos.
Ethics are tightly linked with religion, nationality, culture, and social background. However, science is more concerned with societal needs, economics, and politics of the culture to which researchers belong (Fukushi, 2006). Internationally, legislation has addressed ethical considerations by enacting bans on human cloning, not allowing research embryos to develop beyond fourteen days, and restricting reimbursement for donated embryos (Sandel, 2004). Additionally, there is often a ban on the creation of embryos solely for research purposes. This ban has been considered problematic by some researchers who feel research specific embryos need to be created to effectively research therapies for the most serious genetic diseases (Dickens, 2007).
There are a range of views regarding the sanctity of the human embryo: from those who view the embryo from the moment of fertilization as a human being with equivalent rights and protections, to the other extreme, who view the embryo as no different from any other cluster of human cells. Many feel that there is no definitive moment in the passage from conception to birth that marks the emergence of the human person. Therefore, an embryo at conception possesses the same inviolability as fully developed human beings (Sandel, 2004). The Roman Catholic Church represents the most extreme view, opposing human embryonic stem cell research, in vitro fertilization, and embryo cryopreservation. Some other Christian denominations, Islam, and Judaism have taken a more gradualistic approach, advocating the protection of embryos in states of natural development (Dickens, 2007).
There has been a case that is encouraging for people of faith who support stem cell research. A single cell was removed from an eight-cell embryo for the purpose of preimplantation diagnosis. That embryo, with seven-cells, was implanted and resulted in the birth of a healthy child. This has exposed the potential for embryos to survive the stem cell harvesting process (Dickens, 2007).
Most of the embryos donated for stem cell research would otherwise be discarded. Nothing can be gained from those embryos, which will not result in human babies, but have the potential to spur life saving discovery. Scientists may take a view of donated embryos in a similar way to which surgeon views a donated organ, it is perhaps an unfortunate situation that has presented that organ, but wasting it will not bring its donor back to life (Guenin, 2001).
For the first two weeks following fertilization, an embryo is unattached. It is traveling towards the uterus, it still possesses the possibility of twinning, or recombination. It is not until near day fourteen that it implants and begins to develop the characteristics that define personhood (Guenin, 2001). At the germinal stage, the embryo does not feel pain or have thoughts, nor does it have that which makes one most human, a mind.
At the foundation of Christianity lies the second greatest of the commandments, that one love one's neighbor as oneself. There is an obligation to ease and end suffering when the means are available. All new technologies present both positive and negative emotions while they are being established until they are accepted. Much time has been wasted in debate. The means are available and the treatments are within our grasp. It is not necessary to regard the embryo as a full human being to accord it with a certain respect. It is a precious gift, one that has the possibility of doing great good.
Cohen, C.B., Brandhorst, B., Nagy, A., Leader, A., Dickens, B., Isasi, R.M., et al. (2008). The use of fresh embryos in stem cell research: ethical and policy issues. Cell Press, 2, 416-421.
Dickens, B.M., Cook, R.J. (2007). Acquiring human embryos for stem-cell research. International Journal of Gynecology and Obstetrics, 96, 67-71.
Fukushi, T., Sakura, O., Koizumi, H. (2006) Ethical considerations of neuroscience research: the perspectives on neuroethics in Japan. Neuroscience Research, 57, 10-16. Retrieved May 26, 2009, from ScienceDirect database.
Guenin, L.M. (2001). Essays on science and society: morals and primordials. Science, 292, 1659-1660.
Landis, S.C. (2007, January). The promise and the challenge of stem cell research. Testimony before the Subcommittee on Labor, Health, and Human Services, Education, and Related Agencies United States Senate. Washington, D.C.: U.S. Department of Health and Human Services.
Sandel, M.J. (2004). Embryo ethics- the moral logic of stem cell research. The New England Journal of Medicine, 351, 207-209.
Zerhouni, E.A. (2008, May). Stem cell science: the foundation of future cures. Testimony before the Subcommittee on Health Committee on Energy and Commerce United States House of Representatives. Washington, D.C.: U.S. Office of Legislative Policy and Analysis.