Ethical Analysis of Embryonic Stem Cells
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Running Head: Ethics of Embryonic Stem Cell Research
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Ethical Analysis of Embryonic Stem Cell Research
Every year millions of people suffer and eventually die from serious or largely incurable degenerative diseases of the nervous system (Parkinson’s disease, Multiple sclerosis, and stroke), heart (myocardial infarction), liver (hepatitis), pancreas (diabetes) and other organs. Stem cell therapy could alleviate or possibly cure some of these diseases (McLaren, 2001). Embryonic Stem cells (ESCs) are cells found in a 200 cell, 5 day old embryo that has not yet developed into a fetus or any specialized cells. These stem cells have the potential to develop into any type of cell (Cornwell, 2006). Stem cells derived from embryos can potentially be used to replace existing damaged cells in humans. Because stem cells have not yet differentiated into specialized somatic cells such as skin cells, liver cells, muscle cells, and nerve cells they can possibly be used to develop treatments for degenerative diseases like Parkinsons and Alzheimers, or help to repair damaged tissue from spinal cord injuries, heart-attacks, and strokes. Stem cells might be able to offer victims of heart attack new heart cells to replace damaged cardiac tissue, young individuals suffering from diabetes may be able to receive new insulin producing cells, and individuals whose nervous system has been damaged by disease or injury might be able to see or walk again (Green, 2001). The potential of these cells to replace dead or damaged cells in any tissue of the body may bring about a new field of medicine that leads to cures for diseases now thought to be incurable. Any new experimental medical treatment raises ethical issues for health care professionals and patients, but research on embryonic stem cells raises in addition the ethical conflict between the destruction research causes to embryos and the potential magnitude of benefits (McLaren, 2001). Embryonic stem cell research leads to death of human embryos. Is society justified in destroying human embryos to bring about the potential medical advances that could heal millions of debilitating diseases? When does human life start and are embryos considered humans? Do the benefits of potentially life saving research on human embryos outweigh the destruction caused to embryos? These questions must be analyzed and investigated. Bioethics allows us to study the moral issues of controversial medical topics and make appropriate ethical decisions. Ethical issues of embryonic stem cell research will be reviewed and I will make a decision if it is ethical to perform embryonic stem cell research.
Embryonic stem cells are defined by two properties, first they are cells that can divide indefinitely producing a population of identical offspring. Second, embryonic stem cells can undergo asymmetric division to produce two dissimilar daughter cells (Fischbach & Fischbach, 2004). Embryonic stem cells are the result of the fertilization of the sperm and egg to produce a zygote. The zygote divides several times, by day 2 it is a 4 cell embryo, by day 3 it is an 8 cell embryo, and by day 4 the embryo becomes a compact ball of cells called the morula. Each of the 32-128 cells in the morula is totipotent in that each one can give rise to all cell types in the embryo plus all of the extraembryonic tissue necessary for implantation in the uterine wall. As the morula continues to move through the oviduct, the cells continue to proliferate and the morula enlarges to form a hollow sphere called a blastula this occurs on day 5 (Cornwell, 2006). During the final days in the oviduct and the first days in the uterus a few cells delaminate from the surface layer of the blastula to form an inner cell mass within the cavity. This cluster of cells known as the inner cell mass is the source of embryonic stem cells, the inner cell mass forms prior to the implantation to the uterine wall. Implantation to the uterus occurs 14 days after conception. Human embryo stem cell lines are made by dissecting a 5-6 day old blastula embryo and removing its inner cell mass. At this stage the embryo is composed of approximately 200 cells, including an outer layer of differentiated placental material and the undifferentiated cells of the inner cell mass. The embryo inevitably dies as a result of removing the inner cell mass from the blastula or embryo (Fischbach & Fischbach, 2004).
There are three broad categories of stem cells: embryonic stem cells, fetal stem cells (germ cells), and adult stem cells (Bar-Yam, 2001). Embryonic stem cells are primitive undifferentiated cells derived from the embryos that are pluripotent that is they have the potential to become a wide variety of specialized cells. Fetal stem cells are derived from fetal tissue. They are isolated from the primordial germ cells of the 5 to 10 week fetus. Adult stem cells are undifferentiated cells found in differentiated tissue that can renew themselves with certain limitations and differentiate to yield all the specialized cell types of the tissue from which it originated.
There are four main sources of non adult stem cells. The first source is the surplus embryos that are by product of the activities of in vitro fertilization (IVF). So far the embryos from which human embryonic stem cell (HESC) lines have been derived were almost all donated either fresh or frozen by couples undergoing IVF (McLaren, 2001). A second potential source of HESC result from uniting donated eggs and sperms to create embryos in the lab. Custom made embryos for research raises the question about the ethics of using human embryos solely and explicitly as a means to some end. Excess embryos from IVF clinics that are otherwise destined for destruction are seen by some as a good alternative to creating embryos that will be ultimately destroyed due to research. A Third potential source of HESCs are embryos created through somatic cell nuclear transfer (SCNT). SCNT is the process through which genetic material from a body cell is transplanted into an egg cell. The product of this transplant leads to a cell that undergoes cellular division like an embryo. This allows creation of an embryo without fertilizing the egg with a sperm. Because SCNT uses much of the same technique as cloning and could lead to a cloned individual it has been looked upon negatively by those that oppose cloning (Fischbach & Fischbach, 2004). A final source of non adult stem cells are embryonic germ cells derived from immature fetuses. The use of embryonic germ cells is troublesome in that it associates stem cell research with the emotionally charged debate about abortion.
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