Skip to main content
Markkula Center for Applied Ethics

Unveiling Some of the Ethical Complexities of Human Embryonic Stem Cells

Human embryonic stem cells cropped (Images: Nissim Benvenisty)derivative work: Vojtech.dostal, CC BY 2.5 <>, via Wikimedia Commons

Human embryonic stem cells cropped (Images: Nissim Benvenisty)derivative work: Vojtech.dostal, CC BY 2.5 , via Wikimedia Commons

Christopher Arellano Reyes ’23

Human embryonic stem cells (cropped): (Images: Nissim Benvenisty)derivative work: Vojtech.dostal, CC BY 2.5 , via Wikimedia Commons.

Christopher Arellano Reyes majored in biology and minored in chemistry and biotechnology and was a 2022-23 health care ethics intern with the Markkula Center for Applied Ethics at Santa Clara University. Views are his own.

Within the walls of fertility clinics and research facilities in the United States, more than one million plus frozen embryos rest, each with its own unique story waiting to be told. These embryos, once conceived with the hope of creating life, now exist as enigmatic entities, embodying the ethical complexities surrounding human embryonic stem cells (hESCs). What should become of these embryos? How should society navigate the moral and ethical challenges hESCs present?

hESCs possess remarkable capabilities as pluripotent cells, able to develop into any cell type except the outer trophoblast cells forming the placenta. In contrast to multipotent and unipotent stem cells, which have more limited differentiation potential, hESCs remain undifferentiated, with no gene expression alterations that direct them towards specialized tissues. This undifferentiated state allows hESCs to serve as a blank canvas, where specific growth and differentiation factors can be applied to create desired cell lines. Furthermore, hESCs exhibit self-renewal properties, enabling indefinite replication in culture when provided with appropriate environmental conditions.

Obtaining hESCs involves two primary methods: In Vitro Fertilization (IVF) and Somatic Cell Nuclear Transfer (SCNT). In IVF, eggs are collected from a donor who has undergone ovarian stimulation, and fertilization occurs. On the 5th or 6th day, a blastocyst forms, containing the Inner Cell Mass (ICM) that comprises hESCs. SCNT involves creating an enucleated oocyte and injecting or fusing it with a donor cell nucleus. An electric current activates the embryo, leading to the formation of a blastocyst. 

Using hESCs that would otherwise be discarded to repair damaged or diseased human tissues upholds human dignity because this practice improves human health outcomes while respecting the moral status of early-stage embryos. Despite their significant potential, ethical complexities hinder the full utilization of hESCs.   

Status View of hESCs

The ontological status of hESCs is a subject of philosophical and ethical debate. There are differing perspectives regarding whether hESCs should be considered equivalent to embryos or not. 

On one hand, proponents argue that hESCs, derived from human embryos, possess the potential to develop into full-fledged human beings if provided with the appropriate conditions. They argue that since hESCs are obtained from embryos at an early developmental stage, typically from a surplus of embryos created during in vitro fertilization procedures, they should be regarded as equivalent to embryos. From this viewpoint, treating hESCs as mere research materials or resources may raise ethical concerns, as it could be seen as disregarding the potential moral status and rights of the developing embryo.

On the other hand, some argue that hESCs, in their isolated form, lack the essential features necessary to be considered equivalent to embryos. Let’s focus on the ontological status of the isolated ICM. It is crucial to acknowledge that the isolated ICM lacks the inherent capability to progress into a fetus and eventually develop into a fully formed child. This is primarily because the ICM lacks the trophoblast cells necessary for implantation and the extraembryonic endoderm responsible for nourishing the developing embryo. In light of the aforementioned considerations, the embryonic status is proposed as a more apt characterization wherein the entire isolated ICM can be viewed as a disabled or “non-viable” embryo. It is emphasized that hESCs are incapable of developing into a complete human organism without significant manipulation and external factors. Supporters of this perspective contend that since hESCs cannot independently develop into viable human beings, they do not possess the same moral status as an embryo. 

A Means to an End of hESCs 

The questionable means to an end argument against hESC research is based on the belief that it is not morally justifiable to destroy human embryos, even if it is done with the intention of finding cures for diseases. This argument is often put forward by those who view the embryo as a human life with full moral status from the moment of conception. They argue that destroying human embryos for research purposes is akin to killing a human being, and is therefore inherently wrong. They question how the end goal of healing is justified with a means where we use something with the same moral status as a human. But I say, what’s more ethical, discarding an embryo or giving it meaning by using it for other purposes that improve human health? It’s not merely a means to an end because we are respecting the embryo’s moral status by giving it a purpose while reaching a common end goal of healing and preventing suffering. And this end goal is justified because we are healing individuals in the process and we have the ability to heal individuals from an otherwise incurable condition allowing us to uphold our human dignity by reaching a shared value in healing.  

The Slippery Slope of hESCs

The slippery slope argument is a type of logical fallacy reasoning in which the person making the argument asserts that a particular decision or action will lead to a chain of events, typically negative ones, without adequate evidence to support those events. 

Critics of hESC research often employ this argument by suggesting that accepting the use of hESCs for medical research and therapeutic purposes creates a slippery slope where it becomes challenging to draw a clear boundary between what types of actions or research should be deemed acceptable or not. This argument posits that once hESC research is allowed, it could lead to other unethical practices, such as therapeutic cloning or germ-line gene therapy, without proper regulation or oversight. However, this argument is considered fallacious as it lacks sufficient empirical evidence to establish a causal relationship between the initial action and the subsequent events, thereby failing to provide adequate support for the claim that accepting hESC research will inevitably lead to these practices. But strict ethical guidelines and regulations can be put in place to ensure that research is conducted in an ethical and responsible manner. Rather than assuming a slippery slope and rejecting the use of hESCs altogether, it is necessary to evaluate each type of research on its own merit and ethical considerations. 

Principle of Beneficence and hESCs

Beneficence is defined as acting in a manner where “persons are treat[ed] in an ethical manner not only by respecting their decisions and protecting them from harm, but also by making efforts to secure their well-being.” The argument against hESC research states that beneficence is violated by not respecting both the autonomy and the welfare of the embryos. But what about the beneficence of those in need of hESC research and hESC treatment? Doesn’t the beneficence of those individuals matter? hESC research can lead to significant medical advancements. In particular, we are seeing clinical trials in spinal cord injuries, macular degeneration of the retina, diabetes, heart repair, and the development of a hESC-derived cancer vaccine. These will ultimately benefit society as a whole but most importantly benefit a single person’s life. For an individual seeking a last ounce of hope, hESCs might be the only option, as extensive efforts have already been made to ensure the well-being of that person. 

The Future Direction of hESCs

The future of hESCs holds both remarkable potential and complex challenges. As scientific advancements continue to unfold, hESCs offer a tantalizing glimpse into a future where regenerative medicine becomes a reality. The ability of hESCs to differentiate into various cell types holds the promise of revolutionary therapies for a wide range of diseases and conditions, from neurodegenerative disorders to organ failure. Additionally, ongoing research is focused on improving techniques for generating and culturing hESCs, maximizing their differentiation potential, and overcoming immune rejection concerns. However, the future of hESCs also brings ethical considerations to the forefront. Striking a delicate balance between harnessing their vast therapeutic possibilities and addressing the concerns surrounding embryo destruction and moral implications remains a critical challenge. As we navigate the path forward, it is essential to foster robust dialogue, ethical frameworks, and responsible regulation to ensure that the future of hESCs is guided by both scientific progress and ethical reflection. By doing so, we can unlock the full potential of hESCs while upholding the values and principles that define our society.

Jul 17, 2023

Subscribe to Ethics Center Blogs

* indicates required
Subscribe me to the following blogs:

Make a Gift to the Ethics Center

Content provided by the Markkula Center for Applied Ethics is made possible, in part, by generous financial support from our community. With your help, we can continue to develop materials that help people see, understand, and work through ethical problems.