A recent article in the New York Times by Gina Kolata chronicles the remarkable story of a patient who for many years suffered from type 1 diabetes. After receiving a newly-developed form of embryonic stem cell infusion, he became able to live insulin-free, apparently cured of his blood sugar imbalances.

It was largely a matter of time, funding, and elbow grease before cures of this kind would start to appear. That makes it urgent for us, as a society, to confront and address the ethical questions arising in the wake of these up-and-coming therapies.

We can formulate the ethical question this way: Is it wrong to develop treatments that rely on the direct destruction of fellow human beings who are in their embryonic stages?

It should go without saying that it is always wrong to take the life of one human being to harvest body parts, even to save the life of another human being. Such medicine is fundamentally exploitative and immoral, and ought to be summarily rejected.

Many people are beginning to ask, however, whether receiving a treatment for diabetes developed from embryonic stem cells is really that different from getting vaccinated with a COVID-19 vaccine developed using abortion-derived cell lines?

The two cases are, in fact, quite different.

When it comes to abortion-derived cell lines and their use in developing some of the COVID-19 vaccines, the wrong that was committed involved taking somatic cells (not stem cells), such as kidney cells or retinal cells, from an aborted fetus and working them up in order to prepare a special "cell line" for use in research or vaccine development. The abortion, it should be noted, as wrong as it was in itself, was not performed in order to obtain research material, and the evil of this "corpse raiding" was compounded by not having obtained valid informed consent.

What makes embryonic stem cell-based therapies ethically worse is that a very young human being, still in his or her embryonic stage of existence, is being targeted and intentionally killed in order to obtain the desired stem cells that stand at the center of that medical treatment.

Why, then, would it be morally allowable to receive a vaccine prepared using abortion-derived cell lines, but morally unacceptable to receive a diabetes treatment developed from embryonic stem cells?

Because the type of moral offense and its gravity are different in kind and degree. Directly killing someone to obtain their cells for treatment is different in kind and worse than the wrongdoing involved in taking cells from a corpse, even from a young human whose life was unjustly ended for an unrelated reason. It is always wrong to steal, even from a cadaver. But it's much worse to kill in order to take.

In one case, the researcher himself becomes the executioner who procures cells and tissues from the individual he has just directly and purposefully killed; in the other case, the researcher shows up at the morgue or the abortion clinic following the death, and procures cells or tissues from the individual's body (with the death having occurred at the hands of others and the researcher afterwards profiting from the resultant cadaver). This latter case would not raise ethical concerns at all if researchers were to derive the needed cells from a miscarriage instead of a direct abortion. If an unborn baby girl, for example, were to die of natural causes, her parents could validly grant informed consent for the use of tissues and cells from her body, in effect donating her body to science.

These kinds of distinctions are important, because receiving a diabetes treatment produced with embryonic stem cells signals a willingness on our part to tolerate the killing of younger human beings in order to benefit others who are older. Meanwhile, receiving a COVID-19 vaccine produced using abortion-derived cell lines does not indicate a willingness on our part to tolerate killing for research (since the killing was not done for research, but for some other unrelated motive), and instead indicates a willingness to tolerate cells and tissues that were unethically taken from a corpse.

Should we always avoid using therapies that are produced using embryonic stem cells taken from young humans who were killed in order to obtain the cells? Yes, such therapies are unethical because killing one human being for the purpose of healing another crosses a fundamental moral line.

But the fact that the question is being raised reminds us of the slippery ethical slope that arises whenever we try to use parts of human beings derived from abortions: legally permitting abortion only makes the confusion worse. Hence, there is an urgent need to encourage the use of alternative, non-embryo-derived cell sources by researchers, including cells derived from miscarriages, adult stem cells, or embryonic-type alternatives, such as induced pluripotent stem cells, which can be obtained by genetically manipulating adult human skin cells. These approaches open a path forward in the direction of ethical research and medical therapies.

- Father Tadeusz Pacholczyk, Ph.D. earned his doctorate in neuroscience from Yale and did post-doctoral work at Harvard. He is a priest of the diocese of Fall River and serves as the Director of Education at The National Catholic Bioethics Center in Philadelphia,