On Embryonic Stem Cell Research
A Statement of the United States Conference of Catholic Bishops

Official Documents
Issued by USCCB
June 13, 2008
Copyright © 2008,
United States Conference of Catholic Bishops.
All rights reserved.
Reproduced with Permission

Stem cell research has captured the imagination of many in our society. Stem cells are relatively unspecialized cells that, when they divide, can replicate themselves and also produce a variety of more specialized cells. Scientists hope these biological building blocks can be directed to produce many types of cells to repair the human body, cure disease, and alleviate suffering. Stem cells from adult tissues, umbilical cord blood, and placenta (often loosely called "adult stem cells") can be obtained without harm to the donor and without any ethical problem, and these have already demonstrated great medical promise. But some scientists are most intrigued by stem cells obtained by destroying an embryonic human being in the first week or so of development. Harvesting these "embryonic stem cells" involves the deliberate killing of innocent human beings, a gravely immoral act. Yet some try to justify it by appealing to a hoped-for future benefit to others.

The Imperative to Respect Human Life

The Catholic Church "appreciates and encourages the progress of the biomedical sciences which open up unprecedented therapeutic prospects" (Pope Benedict XVI, Address of January 31, 2008). At the same time, it affirms that true service to humanity begins with respect for each and every human life.

Because life is our first and most basic gift from an infinitely loving God, it deserves our utmost respect and protection. Direct attacks on innocent human life are always gravely wrong. Yet some researchers, ethicists, and policy makers claim that we may directly kill innocent embryonic human beings as if they were mere objects of research - and even that we should make taxpayers complicit in such killing through use of public funds. Thus, while human life is threatened in many ways in our society, the destruction of human embryos for stem cell research confronts us with the issue of respect for life in a stark new way.

Some Arguments and Our Response

Almost everyone agrees with the principle that individuals and governments should not attack the lives of innocent human beings. However, several arguments have been used to justify destroying human embryos to obtain stem cells. It has been argued that (1) any harm done in this case is outweighed by the potential benefits; (2) what is destroyed is not a human life, or at least not a human being with fundamental human rights; and (3) dissecting human embryos for their cells should not be seen as involving a loss of embryonic life. We would like to comment briefly on each of these arguments.

First, the false assumption that a good end can justify direct killing has been the source of much evil in our world. This utilitarian ethic has especially disastrous consequences when used to justify lethal experiments on fellow human beings in the name of progress. No commitment to a hoped-for "greater good" can erase or diminish the wrong of directly taking innocent human lives here and now. In fact, policies undermining our respect for human life can only endanger the vulnerable patients that stem cell research offers to help. The same ethic that justifies taking some lives to help the patient with Parkinson's or Alzheimer's disease today can be used to sacrifice that very patient tomorrow, if his or her survival is viewed as disadvantaging other human beings considered more deserving or productive. The suffering of patients and families affected by devastating illness deserves our compassion and our committed response, but not at the cost of our respect for life itself.

Second, some claim that the embryo in his or her first week of development is too small, immature, or undeveloped to be considered a "human life." Yet the human embryo, from conception onward, is as much a living member of the human species as any of us. As a matter of biological fact, this new living organism has the full complement of human genes and is actively expressing those genes to live and develop in a way that is unique to human beings, setting the essential foundation for further development. Though dependent in many ways, the embryo is a complete and distinct member of the species Homo sapiens, who develops toward maturity by directing his or her own integrated organic functioning. All later stages of life are steps in the history of a human being already in existence. Just as each of us was once an adolescent, a child, a newborn infant, and a child in the womb, each of us was once an embryo.

Others, while acknowledging the scientific fact that the embryo is a living member of the human species, claim that life at this earliest stage is too weak or undeveloped, too lacking in mental or physical abilities, to have full human worth or human rights. But to claim that our rights depend on such factors is to deny that human beings have human dignity, that we have inherent value simply by being members of the human family. If fundamental rights such as the right to life are based on abilities or qualities that can appear or disappear, grow or diminish, and be greater or lesser in different human beings, then there are no inherent human rights, no true human equality, only privileges for the strong. As believers who recognize each human life as the gift of an infinitely loving God, we insist that every human being, however small or seemingly insignificant, matters to God-hence everyone, no matter how weak or small, is of concern to us.

This is not only a teaching of the Catholic Church. Our nation's Declaration of Independence took for granted that human beings are unequal in size, strength, and intelligence. Yet it declared that members of the human race who are unequal in all these respects are created equal in their fundamental rights, beginning with the right to life. Tragically, this principle of equal human rights for all has not always been followed in practice, even by the Declaration's signers. But in our nation's proudest moments Americans have realized that we cannot dismiss or exclude any class of humanity - that basic human rights must belong to all members of the human race without distinction. In light of modern knowledge about the continuity of human development from conception onwards, all of us - without regard to religious affiliation - confront this challenge again today when we make decisions about human beings at the embryonic stage of development.

Finally, some claim that scientists who kill embryos for their stem cells are not actually depriving anyone of life, because they are using "spare" or unwanted embryos who will die anyway. This argument is simply invalid. Ultimately each of us will die, but that gives no one a right to kill us. Our society does not permit lethal experiments on terminally ill patients or condemned prisoners on the pretext that they will soon die anyway. Likewise, the fact that an embryonic human being is at risk of being abandoned by his or her parents gives no individual or government a right to directly kill that human being first.

Cloning and Beyond

It is also increasingly clear that such stem cell "harvesting" will not stop with the destruction of "spare" embryos frozen in fertility clinics. The search for a large supply of viable embryos with diverse genetic profiles has already led some researchers to claim a right to create vast numbers of human embryos solely to destroy them for research. Thus human cloning, performed by the same method used to create Dolly the cloned sheep, is now said to be essential for progress in embryonic stem cell research.

Human cloning is intrinsically evil because it reduces human procreation to a mere manufacturing process, producing new human beings in the laboratory to predetermined specifications as though they were commodities. It shows disrespect for human life in the very act of generating it. This is especially clear when human embryos are produced by cloning for research purposes, because new human lives are generated solely in order to be destroyed. Such cloning for research will also inevitably facilitate attempts to produce live-born cloned children, posing a new challenge to each and every child's right to be respected as a unique individual with his or her own future. Some policy makers offer to prevent this result by mandating that all embryos produced by cloning be destroyed at a certain point, so they cannot survive to birth. These proposals wrongly approve human cloning, while compounding the evil further by insisting that the innocent human victim of cloning must die.

Some researchers and lawmakers even propose developing cloned embryos in a woman's womb for some weeks to harvest more useful tissues and organs - a grotesque practice that Congress has acted against through the Fetus Farming Prohibition Act of 2006. Some would solicit women as egg donors for human cloning research, even offering cash payments to overcome these women's qualms about the risk to their own health from the egg harvesting procedure. Other researchers want to use animal eggs for human cloning experiments, creating "hybrid" embryos that disturbingly blur the line between animal and human species.

It now seems undeniable that once we cross the fundamental moral line that prevents us from treating any fellow human being as a mere object of research, there is no stopping point. The only moral stance that affirms the human dignity of all of us is to reject the first step down this path. We therefore urge Catholics and all people of good will to join us in reaffirming, precisely in this context of embryonic stem cell research, that "the killing of innocent human creatures, even if carried out to help others, constitutes an absolutely unacceptable act" (Pope John Paul II, The Gospel of Life [Evangelium Vitae], no. 63).

A Better Way

Nature in fact provides ample resources for pursuing medical progress without raising these grave moral concerns. Stem cells from adult tissues and umbilical cord blood are now known to be much more versatile than once thought. These cells are now in widespread use to treat many kinds of cancer and other illnesses, and in clinical trials they have already benefited patients suffering from heart disease, corneal damage, sickle-cell anemia, multiple sclerosis, and many other devastating conditions.1 Researchers have even developed new non-destructive methods for producing cells with the properties of embryonic stem cells - for example, by "reprogramming" adult cells. There is no moral objection to research and therapy of this kind, when it involves no harm to human beings at any stage of development and is conducted with appropriate informed consent. Catholic foundations and medical centers have been, and will continue to be, among the leading supporters of ethically responsible advances in the medical use of adult stem cells.


The issue of stem cell research does not force us to choose between science and ethics, much less between science and religion. It presents a choice as to how our society will pursue scientific and medical progress. Will we ignore ethical norms and use some of the most vulnerable human beings as objects, undermining the respect for human life that is at the foundation of the healing arts? Such a course, even if it led to rapid technical progress, would be a regress in our efforts to build a society that is fully human. Instead we must pursue progress in ethically responsible ways that respect the dignity of each human being. Only this will produce cures and treatments that everyone can live with.


1 In general see the site http://www.stemcellresearch.org. Current clinical trials using adult and cord blood stem cells can be viewed at the site ClinicalTrials.gov by using the search term "stem cell." [Back]


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