Science and ethics in the embryonic stem cell debate

The Medieval philosopher, Boethius, tackled the esoteric question of what is a human and came to the conclusion that “human is born of human”. There is a certain circular, facile truth in this conclusion that reminds one of the modern right-to-life refrain that “life begins at conception”—an argument that seems as unsatisfying as any argument that has been reduced to a cliché. It is repeated so often and so glibly that the basis of the argument goes unexamined and unchallenged. 

This “life begins at conception” reasoning, leads to a casuistic rhetoric where harvesting embryonic stem cells (ESCs) from a five day old human embryo called a blastocyst, for the purpose of treating human ailments, is akin to killing a living adult in order to harvest his organs to transplant into someone else.  But how do we cross the chasm of logic to believe that a blastocyst is the moral equivalent of an adult human?  This is an unexamined and unspoken conclusion that looks very different in the light of modern biology.

Before exploring the premises underlying the right-to-life position let me acknowledge that at this point, some will ask, why revisit this debate?  Haven’t embryonic stem cells been rendered unimportant in the face of the research success of adult stem cells and in view of the fact that we can now reprogram adult cells to become stem-like, thereby avoiding the destruction of embryos to harvest ESCs?

Not so fast.

The fact is that we are rapidly driving, some would say careening, toward the day when ESCs will be used to treat patients. Despite the exciting advances in stem cell alternatives, ESCs still play a role that adult and reprogrammed adult cells cannot supplant—yet.

"...FDA recently approved the first ESC clinical trial..."

The FDA recently approved the first ESC clinical trial to treat patients with spinal cord injuries. The California Institute for Regenerative Medicine that oversees the $3 billion stem cell investment that came out of Proposition 72 in 2004, recently awarded grants specifically for supporting research leading to FDA applications to use ESCs for experimental therapeutics. A medical doctor in India claims to have treated a quadriplegic with human ESCs, with modest results.  Doctors in other countries make similar claims, raising the specter of unregulated “stem cell” tourism and unfettered treatment of patients with insufficiently tested ESC therapies—unregulated clinical trials in reality.

As we rapidly approach the era of stem cell therapy, or regenerative medicine, if in fact we are not already there, the debate over whether this technology represents a “brave new world” or a Faustian bargain will only intensify and I believe it will do so very soon. At the moment, this debate seems to be in a latent period due to the recent discovery that adult cells can be reprogrammed into stem cells. Opponents of ESC research hope that this advance will negate their ethical concerns about destroying human embryos in order to obtain stem cells. After all, if you can pluck a skin cell from someone’s arm, put it in a broth and, presto, pull a stem cell out, why would anyone need or want to do research with stem cells obtained from an embryo? But, the inconvenient truth behind these reprogrammed cells has not been fully explained. The fact is that they, too, have the potential to develop into persons. A scientist at MIT reprogrammed a mature mouse blood cell into a stem cell and used it to derive a whole new mouse. Very recently, two groups in China reported doing the same thing beginning with mouse fibroblasts and ending up with cloned animals. Let us consider how this ability of these so-called induced pluripotent stem cells (iPS) affects the whole stem cell debate.

Unpacking the right-to-life argument

I’ll begin by unpacking the right-to-life argument that “life begins at conception. It is abundantly clear that when a sperm fertilizes an egg cell, a cellular entity is created that can grow into a fully developed person. So, in a sense one can indeed claim that “life” begins at fertilization. But this argument assumes, and leaves unstated, that society is, therefore, obligated to give the same level of respect to a fertilized egg as it gives to an adult human. 

"...when is society obligated to give full respect to human life."

Thus, the underlying ethical argument here really is not about “when life begins” (indeed there is no precise time where this happens—it is a process lasting a couple of days), but about when is society obligated to give full respect to human life. This is the essential ethical issue on which the whole debate should focus. 

Let me illustrate the idea this way: We all agree that a living woman deserves our full moral consideration; society cannot legitimately take her life or deny her other life-related freedoms without good cause, such as committing a crime. On the other hand, neither a live dog nor a clearly dead human elicit the same level of consideration from society. This means that simply being alive, as in the case of the dog, or simply having a human body, as in the case of the corpse, do not provide a sufficient basis for assigning the full moral consideration that we give the woman. It follows that there is something inherent in the adult woman that we all readily recognize, but that we, equally readily, do not see in a live dog or a dead person, which tells us she deserves a greater level of moral respect.  This inherent worth in the woman that we all innately recognize is the crux behind making sense of the embryonic stem cell debate.

Viewed in this way, the question with ESC research becomes this: does a blastocyst that was created by a human (through in vitro fertilization) and that lives in a petri dish and lacks a brain, personal history, personality or any recognizable human trait is the moral equivalent of a living adult human that enjoys all these attributes?  Do we innately recognize something in the blastocyst, like we do in the woman, which compels us to assign full moral recognition to a five-day old sphere of cells that is no larger than a period at the end of a sentence?

At this juncture, some will argue that the fertilized egg possesses a completely novel human genome that denotes a unique genetic human being, and that this makes it deserving of full moral consideration by society. But, this argument has this major problem; certainly, genetic makeup is necessary and sufficient for determining that an embryo is Homo sapien, but genetic makeup, no matter how unique, is not sufficient for determining moral standing. If it was, then skin cells, which have the same genes as the fertilized egg from which they came, should also have equal moral standing with the fertilized egg.  

"...to acknowledge that a fertilized egg has potential to become a person means
that, in fact, it is not a person at that time."

It also could be argued here that an important difference between a fertilized egg and a skin cell is that the former has the "potential" to develop into a mature human person, while the latter does not. But there are problems of both semantics and logic with this contention.  For instance, "potential" describes something that can, but has not yet come into being. In other words, to acknowledge that a fertilized egg has potential to become a person means that, in fact, it is not a person at that time.

Furthermore, it is not logical to assume that “potential” confers any a priori obligation--while I may have the “potential” to become President, that obligates no one to play “Hail to the Chief” when I enter a room. So, based on potential, there is no compelling reason to afford a blastocyst the same obligation we offer the adult woman.

Conditional potential of stem cells

It also is important to understand that a thing’s “potential” can be altered by circumstance. Thomas Aquinas, the great Catholic theologian and philosopher, made this argument about “potential” many years ago. He explained that for potential to be present, a thing must have the capability of realizing that potential. Thus, a piece of paper has the potential to be burned, because it is burnable. Conversely, a bucket of water does not have the potential to be burned because it is not capable of being burned.

Certainly we now know that water can be given the potential to burn, but only under specific electrolytic conditions that separate oxygen and hydrogen from the water molecules. So, the conditional circumstances in which water exists determine its potential to be burned.

In the laboratory, human ESCs are harvested from a blastocyst that has only lived in a tissue culture dish. As long as a blastocyst lives in the petri dish, it has zero potential to become a person. This can only happen if someone intentionally inserts it into the womb of a woman who has been hormonally manipulated to mimic pregnancy. Only after these human efforts, like the human efforts needed to make water burnable, can the tissue culture organism then acquire the potential to become a person. 

From animal cloning, which is now a common practice, we know that under the proper conditions, we can reprogram adult cells back to an embryonic state where they acquire the ability to grow into an embryo and a fully functioning animal. Therefore, modern science tells us that, like a blastocyst that lives in a petri dish, a blood cell that lives in your veins has conditional potential to develop into a person. Since we do not confer any special moral status to a blood cell what then compels us to confer such status to the blastocyst that was created in a laboratory and that lives in a petri dish or frozen in a liquid nitrogen tank? After all, they both have similar conditional potential to become a person.

Thus, like genetics, “potential” is not a sufficient basis to compel us to confer the same moral status to a fertilized egg that we reserve for a living person. 

At what point do we give a developing embryo full moral consideration?

It, admittedly, is very hard, if not impossible, to know when we ought to bestow full moral protection to a developing human embryo. But, I submit that we can know when the embryo does not enjoy the same consideration we give to an adult. To illustrate this point, consider this thought experiment—you walk past a building and see a fire raging inside.  Moreover, you also see a man struggling to get off the floor and escape the conflagration. You see that he is lying next to a tank that you know contains thousands of frozen human embryos.  What would you do if you only had time to make one trip into the burning building? 

"Most of would opt to rescue the man..."

Most of us would opt to rescue the man indicating that we recognize a greater moral responsibility to one anonymous living adult person than we do to a tank full of nascent persons. Indeed, most of us would opt to rescue a dog before the tank of embryos. In other words, we do not innately view thousands of five-day old embryos as moral equivalents to a single fully formed person any more than we view a live dog as the moral equivalent of the woman. To do so, we have to conjure up a special respect for embryos that is based on the imperfect arguments discussed above.

Unfortunately, poor Boethius, a Christian, ran afoul of the Visigoth rulers of Rome and was executed in an especially gruesome way. They wrapped a rope around his head, inserted a stout stick and twisted it until his skull burst. I suspect that when the right-to-life community becomes aware of the ability of reprogrammed adult cells to become people, the debate will flare once again generating Boethian-sized headaches on both sides.

© 2009 Steven S. Clark, PhD, all rights reserved. 

Disclaimer: The authors used their best efforts in collecting and preparing the information published herein. However, neither Steven S. Clark, nor other authors, assume, and hereby disclaim, any and all liability for any loss or damage caused by errors or omissions, whether such errors or omissions resulted from negligence, accident, or other causes.                                     

Comments

[research paper writing]

Well, I have been reading your blog posts daily and the reason I come on your blog frequently is its compelling content… Regards…

[Ralf Kettenhofen]

Dear Steve,

what do you understand with the expression 'human cloning'? One has really to take care to use such expression in the right context and it shows that the scientist involved in the issue of pluripotent stem cell science (like myself) have to communicate the principals and results of their work much more intensively with the public.

‘Human cloning’ my imply that it is necessary to engineer a complete human being (like with the cloned sheep Dolly). Even worse, some people might remember the Hollywood thriller ‘The Island’ with Ewan MacGregor where humans have been cloned and used as spare parts storage of new organs for wealthy but diseased clients.
Taken from cell science 'cloning' means that you take a single cell and let it grow to obtain a population of cells with the same genetic background.

There was great progress in the human pluripotent stem cell research in the last one and a half years. Now it is possible to reprogram somatic cells like fibroblast from any the skin of any human being in order to obtain pluripotent stem cells. These cells are called 'induced pluripotent stem' (iPS) cells.

The definition of pluripotency comprises two main issues. The first is that they can differentiate potentially into all cell types of the body and secondly that the stem cells themselves can be kept in culture without loss of their properties in regards of growth and the potential to differentiate.
So these cells will for sure be used for regenerative medicine sometime in the more far future because there will be no rejection of the transplants anymore. Still there are at least some hurdles that have to be overcome in the way how the iPS cells are to be generated.

Much more closer to reality is the application of the human iPS cell-derived cells and tissues for science and pharmaceutical drug development. And this exactly what is going on at the moment.

The most important aspect of human iPS cells is that it is no longer a need to scarifies embryos or to superovolate women with high doses of hormones to get the oocytes for nuclear transfer in order to obtain pluripotent stem cells.

Coming back to your question. To my mind the human iPS cells have to potential to revolutionize drug discovery and medicine in a positive way.

Best regards,

Ralf

[Steven S. Clark, PhD]

"The embryo is a fully whole organism of the species homo sapien"

Roger, you simply are re-stating the canard that "life begins at conception", which I asserted in my article is an insufficient basis on which to assign full moral standing to an embryo. I won't recreate the argument here, but refer you to my original essay.

"The embryo is actively developing into the next stage of human life."

This is the argument of "potential", which, again, I pointed out is an insufficient argument. As I said in my article, this potential does not exist if the embryo is in a petri dish or frozen in a liquid nitrogen tank. In these environments it most certainly is not "actively developing."

Thanks for your comments.

[Roger]

Mr Clark's opening statement of his rebuttal sidesteps my main criticism: "What is missing from the previous critiques is a positive statement of why we are obligated to view an embryo as having the *same* rights as a living person (emphasis mine)".

The ethical objection to embryonic stem cell research does *not* (necessarily) assert that an embryo has the *same* rights as a living person (although this claim can certainly be made). The objection asserts only that this stage of life has a status that makes it unethical to treat it as property whose existence can be created, manipulated, and destroyed solely for the benefit of others. By arguing against a higher standard, Mr Clark is implying that this higher standard is necessary to sustain the objections against this research (it is not).

This is a complex subject, but let me state at least 2 relevant qualities of a human embryo that make it deserving of a status that should prohibit its treatment as property.

a) The embryo is a fully whole organism of the species homo sapien. Embryos can thus not be compared to cells, tissues, or non-essential organs from a fully developed organism. When a component of a human being can be removed without endagering the life of that human being, then there are many fewer ethical considerations. When the removal or manipulation of cells, tissues, or organs *kills* the organism (or in this case is the entirety of this organism), then a completely different ethical framework is involved.
b) The embryo is actively developing into the next stage of human life. It requires no external agent or outside force other than its natural environment containing nutrition, temperature control, etc to continue evolving. It certainly has "potential" but it has much more than that. The progress of this life to its culmination at birth is an uninterrupted series of natural cell divisions with no qualitative difference than the cells divisons taking place at the moment the embryo is frozen (or destroyed).

One can of course talk about a lot of qualities that an embryo does not have such as human conciousness, pain sensation, etc. but these qualities are not necessary to sustain the objections to embryonic stem cell research. These qualities might argue for a greater set of rights for a fetus (and still greater for a living person) than an embryo. I would assert, however, that the bare minimum rights that should be afforded to a live autonomous, rapidly-growing, organism of the species homo sapien should prohibit the practice of creating, manipulating, and destroying them at will by others for the benefit of others.

Mr Clark might point out that my assertion not only has implications for embryonic stem cell research but for current practices of assisted reproductive technology. And he would be right.

[Steven S. Clark, PhD]

What is missing from the previous critiques is a affirmative statement of why we are obligated to view an embryo as having the same rights as a living person.

Perhaps I am missing some compelling point in the right-to-life argument, but I tried to hit the points I do know. I also see no refutation of my points that the right-to-life argument is insufficient on which to base an ethical stand.

"Mr. Clark has distorted the issue by trying to make an argument against an embryo having the full legal standing of an adult."

The embryo having equal moral status as an adult is the central tenant of the right-to-life position, is it not? Addressing this head on is not a distortion.

"Would you say that the classification of "living person" is applied externally, by a group of other previously-classified "living persons""

Yes. And is it consistently applied--yes, except in fringe circumstances, such as "brain death" and it is not wise to base an ethic solely on fringe cases. As I mentioned, it is not possible to have consensus agreement on precisely when an embryo/fetus enjoys full moral consideration. But, there are times when we know it unambiguously does not, just like there are times when we know unambiguously that a man is dead.

Thanks for your comments.

[Roger]

I agree with Mr Clark's proposal that the ethics surrounding the embryonic stem cell debate should hinge around the legal recognition given to human life at the embryonic stage.

I agree with little else in this piece. To make a long comment short, yes it is true that society will probably not give the same recognition to an embryo as it does to a fully grown adult. I'll go further and say that an embryo is probably not deserving of *all* of the legal recognition given to a viable fetus.

These are straw-man arguments, however, because the opposition to stem cell research comes from the assertion that just the *bare minimum* rights or standing afforded to an embryo are violated by allowing an embryo to be created in petri dishes, kept in freezers, and disposed of at will by its biological parents and society at large.

Mr. Clark has distorted the issue by trying to make an argument against an embryo having the full legal standing of an adult. What he is really trying to blithely justify, however, is an embryo having NO standing at all. Mr. Clark is trying to justify research that treats a life human embryo as *property*, one whose purpose and existence can be completely controlled for the good of others. If human embryonic life is given *any* standing at all (even if it's miniscule appeared to the standing of a born child), then this standing prohibits the practice of this research.

[Paul Szews]

One question Steve: Would you say that the classification of "living person" is applied externally, by a group of other previously-classified "living persons", as might a jury judge a defendant to be innocent or guilty?

Or is there something inherent to a "living person" that makes him or her both "living" and a "person" regardless of the external perspectives, opinions and experiences of other "living persons"?

And one more, if you please: Can the "living person" classification be revoked after it has been applied, and if so, under what circumstances?