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Controversy Over the Use of Embryonic Stem Cells in Research

Written by Margaret Wei

Stem cells have been increasing in popularity in research in recent years due to their pluripotency. Stem cells are at first unspecialized, but have the capacity to develop into specialized cells — hence their valued versatility when it comes to research. Stem cell research is used to increase understanding of how diseases occur. Researchers do this by observing how the stem cells differentiate into the specialized cells (bones, heart muscle, nerves, and other organs and tissue) to better determine how diseases and conditions develop. 


Origin of Stem Cells

Several different types of stem cells are used in research: embryonic, adult, induced pluripotent, and perinatal. Embryonic stem cells originate  from donated fertilized eggs in vitro fertilization clinics but never implanted in a woman’s uterus. Adult stem cells are derived from tissue, like bone marrow, and can be used to grow different types of specialized cells. Induced pluripotent stem cells are manipulated through genetic reprogramming to transform adult cells to stem cells, and then they can be used to replace dysfunctional cells. Perinatal stem cells come from amniotic fluid and can develop into specialized cells. In laboratories, stem cells can live and grow in special solutions in test tubes or petri dishes

Of the different types of stem cells, embryonic stem cells are the most controversial because their research consists primarily of experimentation on cells that have the potential to become a developed human. These cells are derived from embryos at a developmental stage before implantation would normally occur in the uterus. During this time, fertilization occurs in the oviduct, and over the span of the next few days, the cell divides multiple times as it travels to the uterus. At this point, the embryonic cells are undifferentiated, in other words, they do not look or act like the specialized cells of the adult, and they have the potential to become any specialized adult cell type (Yu, J. and Thomson, J.A.). 

The first stage of differentiation occurs after five days, and an outer layer of cells that was supposed to become a part of the placenta separates from the inner cell mass (ICM). Because of the process of implantation, the ICM cells no longer have the potential to develop into any cell type of the body, and they are quickly depleted as they differentiate into limited types of cells. Eventually, the ICM-derived cells are fixed to be embryonic stem cells if the ICM is removed from its normal embryonic environment and cultured under appropriate conditions. These specific conditions allow the cells to proliferate and replicate, while maintaining the developmental potential to form any cell type of the body (Yu, J. and Thomson, J.A.).

The diagram above illustrates the process of obtaining embryonic stem cells. 

Interactive resources for schools. (n.d.). Retrieved December 30, 2020, from


Embryonic Stem Cells in Research

Stem cells are currently used in regenerative medicine where healthy cells are generated to replace diseased cells. Scientists use embryonic stem cells to determine how specific cells can be used to regenerate and repair diseased or damaged tissues in people. Further research on stem cell regeneration would be beneficial to those who have Parkinson’s disease, Alzheimer’s disease, heart disease, stroke, burns, cancer, etc. The potential that stem cells have to become new tissue can be used in transplant and regenerative medicine. 

To ensure that drugs are safe to be used on people, researchers use stem cells to test drug effectiveness before it gets approved for drug development for cardiac toxicity testing. The stem cells that are to be tested on must be programmed to acquire properties of the type of cells targeted by the drug, but more research needs to be done about how to program cells into specific cells to produce more accurate results from the tests that would show what kind of effect the drug had on the cells (Railton, 2019).


Stem Cell Controversy

Despite the benefit of the pluripotency of embryonic stem cells, controversy arises behind how embryonic stem cells originate. Because embryonic stem cells are extracted from human embryos, many scientists question the ethics of embryonic stem cell research because it is correlated to human testing. Additionally, many disagree with testing on embryonic stem cells because the fertilized embryo has the potential to develop into a human. Concerns arise about what qualities determine humans along with the pervasive debate of what constitutes as the official beginning of human life during embryonic development. 

According to certain faiths and religions, “human life begins at conception,” meaning that an embryo is equal to a person and it has the same rights that must be respected. As a result, the scientific process of extracting the embryonic stem cell from a blastocyst and removing the inner cell mass is amounting to murder (Lo, B., & Parham, L., 2009). This mindset is commonly correlated to the opposition of abortion and with the “pro-life” movement. However, a number of pro-life leaders support stem cell research using frozen embryos that remain after a woman or couple has completed infertility treatment and that they have decided not to give to another couple.

According to Senator Orrin Hatch, a former U.S. senator and a representative of the conservative party interposed the idea that, “I believe that human life begins in the womb, not a Petri dish or refrigerator … To me, the morality of the situation dictates that these embryos, which are routinely discarded, be used to improve and save lives. The tragedy would be in not using these embryos to save lives when the alternative is that they would be discarded.”

A moderate view that others possess in terms of the morality of the embryo would be that the embryo would develop into a person later in development, well after fertilization. This view  believes that a newly fertilized embryo does not constitute the same characteristics as a developed individual. However this does not always mean that they do not fully believe that embryonic stem cells are solely a “clump of cells” and that it is ethical for research without restriction. This does not mean that they do not agree with embryonic stem cell research, many hold a middle ground in which the embryo deserves to be perceived as a potential human being, but it is acceptable to use for certain types of research given good scientific justification, careful oversight, and informed consent from the embryo donor for research (Lo, B., & Parham, L., 2009).


Solutions to Reduce Controversy

Due to the rising controversy on this topic, The National Institutes of Health created guidelines for human stem cell research in 2009, which stated how they may be used in research. Also, to ensure that ethics are not violated, the guidelines state embryonic stem cells from embryos created by in vitro fertilization can be used only when the embryo is no longer needed.

Additionally, to reduce the controversy surrounding the idea of the potential of embryonic stem cells to develop into a human, scientists began to use pluripotent stem cells as an alternative. Since pluripotent stem cells are genetically reprogrammed to transform adult cells into stem cells, they do not have the same ethical concerns as embryonic stem cells. Therefore, genetically reprogrammed pluripotent stem cells do not have the same ethical concerns as embryonic stem cells in terms of origin.



Lo, B., & Parham, L. (2009, May). Ethical issues in stem cell research. Retrieved December 27, 

2020, from

Orive, G., Hernández R.M., Gascón A.R., Igartua, M., Luis Pedraz, J. (2003, Mar). 

Controversies Over Stem Cell Research. Retrieved December 29, 2020, from

Railton, D. (2019, Feb). Stem cells: Therapy, controversy, and research. (n.d.). Retrieved 

December 27, 2020, from

Yu, J. and Thomson, J.A. Embryonic Stem Cells. (n.d.). Retrieved December 30, 2020, from

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