What follows is a discussion of an issue with many empirical aspects to it. Because pro-lifers have been urged to get on board with the proposal in question, I think it's important for us to have an informed opinion. The empirical statements in what follows all have evidence for them, but I am interested in and open to corrections of any of them, the more so as I am not an embryologist and have studied these matters only as an amateur.
The procedure in question is called ANT-OAR: Altered nuclear transfer oocyte assisted reproduction. My position is that ANT-OAR is wrong, not primarily because the entities it would produce would be human embryos (in one current versions of the proposal, I'm presently inclined to think that they would not be), but even if the entities it produces are not human embryos. My position against ANT-OAR is thus, as far as I know, original in the debate.
ANT-OAR has been held up as a method by which embryonic stem cells can be produced without producing human embryos at all. A number of sincere and ethically careful people, most notably William Hurlbut, have been assiduously working on the concept of ANT-OAR in the hopes that it will provide a place where pro-lifers and proponents of embryo-destroying research can agree. Their hope is that this will free pro-lifers from the accusation that they are holding up scientific progress and foreclosing on the possibility (still only theoretical) of disease cures from embryonic stem cells. (See the statement on ANT here, with as endorsers not only Dr. Hurlbut but also such pro-life luminaries as Robert P. George and Hadley Arkes.)
Wesley J. Smith has recently linked an article in Nature Reports Stem Cells in which Marcus Grompe, a scientist at the Oregon Stem Cell Center, advocates ANT. To his credit, Grompe says outright that research that involves destroying IVF embryos should not be done, and he even goes so far as to say that such embryos have souls, which is an astonishing statement to see published in such a journal. But he believes that ANT is a project that we can all get behind.
There is a great deal to be said here, and this post will already be long enough, but at the outset I should say that even aside from the serious ethical issues, scientifically, pragmatically, and sociologically, ANT-OAR proponents are on the wrong track. Adult stem-cell research has proven very promising. Embryonic stem-cell research is not only unproven as far as curative potential, there is also the serious question of tumor causation as a result of the very pluripotency that is so coveted in embryonic stem cells. Moreover, no pro-lifer is going to get any credit whatsoever from a committed embryonic stem cell proponent for urging ANT-OAR. To those who believe in the human sacrifice that is embryo-destroying research, nothing less than full freedom, with federal tax funding, to pursue that avenue is acceptable. So I'm inclined to think there is little point from any angle in pursuing ANT-OAR.
But the more serious question is whether ANT-OAR is morally wrong. To understand all of this, a little background, which may be redundant for some readers: Cloning involves producing a mammalian zygote by taking a somatic cell nucleus and transfering it into an enucleated egg. In the process of the fusion of the egg with the genetic information in the somatic cell nucleus, a totipotent cell--a zygote--comes into existence and the egg and somatic cell nucleus cease to exist as separate entities. The genetic information in the somatic nucleus is thrown into a different epigenetic state so that it isn't "the nucleus of a skin cell" but rather the nucleus of a totipotent cell. From there on, the development of the embryo continues normally, assuming that it is successfully implanted within the requisite window of time. At about five days along (in the case of humans) the first level of cell differentiation takes place when the embryo comes to be called a blastocyst. Instead of all the cells being the same, there are now two levels--an inner cell mass, composed of pluripotent cells, and a trophectoderm layer which will in the continued development of the embryo "turn into" the placenta, an essential organ of the embryo's (and later the fetus's) own body, carried outside the body. The inner cell mass will, in the continued course of normal development, differentiate into everything else--in other words, it will develop into the embryo proper.
Standard embryo-destroying research usually begins with IVF embryos which have been conceived not by cloning but by the mixing of egg and sperm in the lab. Scientists strip the trophectoderm layer off, harvest the inner cell mass, and then culture the inner cell mass, using it to develop stem-cell lines.
With all this in place, here we go: Earlier proposals for ANT (known simply as ANT without the OAR) were in my opinion quite clearly wrong as it was plausible that what those procedures would make in the lab would simply be damaged human embryos. The earlier ANT proposal involved simply knocking out a gene in the somatic cell nucleus before implantation, a gene necessary for the later development of the trophectoderm layer. The concern there was that what would be brought into existence when the altered somatic nucleus was placed into the enucleated egg would appear at first to be a normal human zygote but would simply fail properly to develop a trophectoderm at the blastocyst stage and hence would die. In other words, it looked like this proposal would merely produce an embryo with a fatal flaw.
The more recent proposal involves doing more than merely the negative step of knocking out the gene in the somatic cell but also encouraging (I don't know how, but I assume they do) the production of what is known as a "transcription factor" called nanog in the somatic nucleus. The theory is that this forced expression of nanog and perhaps also the introduction of nanog separately into the enucleated egg would guarantee that when the egg and somatic nucleus fuse the result will be, from the beginning, a pluripotent cell like that of the later inner cell mass. Hence--so runs the theory--the desired ICM cells could be produced without the entity's ever having passed through a totipotent zygote stage in the first place.
As far as I know, this method has not yet been tried, not even in mice. The only thing that appears to have been tried in mice is the gene knock-out procedure. So it isn't clear if this would all go the way ANT-OAR proponents are speculating, even in animal studies.
Grompe apparently sees no significant moral difference between the gene-knocking and the positive-factor versions of ANT. He implies that both are morally acceptable, but Hurlbut et. al. appear to be leaning rather heavily on the distinction between them.
Some critics of ANT-OAR argue that in the very nature of the case, there must a moment, however brief, when the cell formed in the nuclear transfer process is a human zygote. (See Adrian J. Walker, p. 774, footnote 10, here. Links to the rest of the articles in the Communio exchange can be found here.) But as far as I can see, this position is purely a priori. What Walker does not appear to be considering is the possibility--which apparently is what the ANT-OAR proponents are counting on--that it is the process of fusion with the egg itself that produces the type of cell in question. This appears to be what happens in ordinary cloning. It is apparently the process of the somatic nucleus's fusion with the enucleated egg that does the "reprograming" of the genetic information to produce a new cell which, from the time it first exists as a complete cell, is neither a skin cell nor an egg but a mammalian zygote. Similarly, the claim in ANT-OAR appears to be that it is the very process of fusing the altered somatic nucleus with the enucleated egg that does the reprograming so that the new cell produced is from the outset neither a skin cell nor an egg cell nor a zygote but rather a pluripotent cell like those of the blastocyst inner cell mass. That this will happen I don't know. That it is impossible in principle is far more than I can say.
Suppose that we grant for the sake of argument that the process of ANT-OAR goes the way its proponents say and that it produces from the first moment nothing but pluripotent cells like those of the inner cell mass of a blastocyst. The first question, then, is whether such a pluripotent ICM cell would be a human embryo. The argument for this proposition is simply that, after the blastocyst differentiation takes place in the course of normal development, it is the pluripotent cells of the inner cell mass that later do turn into all of the human embryo except for the placenta. And, so this argument runs, just as we would not say that a later fetus without his placenta is not a human being, so we should not say that a pluripotent ICM cell without the trophectoderm is not a human being.
I'm presently not convinced by this argument. Going back to the process of embryo destructive research, it seems to be generally agreed that the harvesting step in which scientists strip the trophectoderm layer and take the ICM for culturing does indeed kill the embryo. Given that this is the case, it appears that the ICM without the trophectoderm should be regarded not as a complete and living embryo but rather as the dead body of an embryo, or nearly all of the dead body, the part wanted by scientists for research. This is why the cultured ICM cells, even though they are receiving sustenance, do not continue to differentiate and develop as embryos. A parenthetical note on this reasoning is that it therefore looks to me as though the trophectoderm has a more important role than merely turning into the placenta later on. The trophectoderm is not yet the placenta at the blastocyst stage, and its presence as an outer layer appears to be necessary in some way beyong the roles assigned later to the placenta (providing a means for the provision of oxygen and nutrition) for the further differentiation and organization of the inner cell mass into the visible embryonic body. There may well be people out there who know how and why the trophectoderm is necessary for this process, but I am not one of them.
Now suppose that the inner cell mass of the blastocyst after harvesting in embryo-destroying stem cell research should be regarded not as a living embryo but as the dead body of an embryo. In that case, what ANT-OAR proposes to produce, by producing ICM cells immediately, is something just like the dead body of an embryo.
It seems to me that producing such an entity is morally wrong, even if ANT-OAR goes just the way its proponents want it to go. Proponents of ANT-OAR often analogize the process to producing some sort of obviously non-embryonic tissue. One early analogy was to a teratoma--a form of cancer. Grompe compares ANT-OAR to producing muscle cells. But of course pluripotent ICM cells aren't muscle cells and they aren't cancer. If they were either of these, they wouldn't be useful for the work that scientists hope to do with them. The reason they are desired is precisely because they are just like the part of a blastocyst that will later develop into the whole visible body of the embryo. It is precisely because they have the capacity to turn into all the organs and tissues of the embryo other than the placenta that researchers want them. In other words, it's precisely because they are just like the dead body of the embryo harvested when an IVF embryo is killed that they are the goal of ANT-OAR.
So I propose a different analogy: Suppose that in some sci-fi scenario a scientist (I'm inclined to call him a mad scientist) could build an exact physical duplicate of your body from the feet up, stopping before making the head. This built, decapitated body would not have developed from anything that ever was or ever looked like a human embryo, zygote, or baby. The scientist built it, let's say, in his lab. He doesn't put a head on it, either because he can't or because if he did it might come to life, and then you'd have ethical problems. So he's succeeded in building something that is just like your decapitated body, without its ever having been alive in the first place. Neat trick! Now it can be used for spare parts for you if you need an organ transplant.
Doesn't this raise ethical concerns in itself?
I propose a principle. You might think it's just obviously wrong or obviously right, but I propose it for your consideration:
A whole human body or nearly-whole human body, even if not living, should not be an object of manufacture.
I have to admit that this principle seems to me self-evidently true on its face. This is despite the fact that it goes farther than the usual objection to cloning--that a living human person should not be an object of manufacture.
I think that those who recognize the exceptional nature of human beings and an important connection between this exceptional nature and the human body should accept the principle for that reason: Human beings are special. Human beings are in their natural and normal state embodied agents. Human specialness confers specialness on the human body, which should therefore be treated with particular respect. It is not respectful in the relevant sense to build a whole or nearly-whole human body. Hence, etc. Christians recognize the specialness of the human body because they accept that man is made in the image of God. The implications of the specialness of the human body are, of course, highly controversial even among Christians. But I believe that the sense of revulsion at the sci-fi scenario sketched above (the Faceless Frankenstein scenario, we might call it) is evidence that a violation of the special nature of the human body is taking place in that scenario. If the analogy holds to making pluripotent cells, then the wrongness transfers to that process as well.
One argument against the principle I'm promoting is that there seem to be morally unproblematic acts in which scientists do "build" parts of human bodies. Adult stem-cell work itself is like this: Multipotent cells are encouraged to change their epigenetic state so that they turn into nerve cells and other cellular types needed for disease treatment. Is there a principled line that is crossed when we are not merely making muscle cells, nerve cells, or blood cells directly from already-differentiated cells but rather are first making pluripotent cells? I believe that there is. It seems to me morally significantly different if the process involved never passes through a stage that is anything like making a complete or near-complete human body. Hence I don't think my argument also rules out adult stem-cell research.
Unfortunately, though, if indeed pluripotent cells exactly like those of the ICM are wrong to make for the reason I've given, we should not be pursuing any avenues for making them and should rather be relying only on cells that are differentiated to a further level than pluripotency, and trying to turn them directly into the tissue types needed, as is done presently in adult stem cell research. But we should not be pursuing research (mentioned by Grompe) to try to take adult cells and "turn the clock back" on them so as to turn them back into fully pluripotent cells, from which they would then be redifferentiated later into cell types needed for treatment. This might itself seem to be a counterintuitive result of my position. Surely, it might seem, if we can coax adult cells into turning back into something just like ICM cells without even using a somatic nuclear transfer technique that looks like cloning, we haven't done anything wrong. Why, in that case, all we worked with to begin with were your own adult cells.
But these days, we have to admit that we are already to some extent living in a world of science fiction. Who would have believed, three hundred years ago or even fifty years ago, that a sheep could be made by cloning itself? And cloning starts with what appear on the face of it to be unpromising materials--an enucleated egg, an ordinary cell from an adult body. In fact, if we were cloning a female, both of these could come from the same person in the first place. If scientists can make an entire baby sheep starting with a somatic cell and an enucleated egg, it shouldn't be all that surprising if they eventually find a way to make something just like the dead body of a mammalian embryo without bothering with the egg. Grompe points out that in any event the "turn back the clock" sort of research appears to have great practical obstacles in its way, but if it happens, we should be willing to face the fact that doing so might be immoral for Faceless Frankenstein reasons. So I'm willing, for the time being anyway, to bite that particular bullet.
Readers will have to draw their own conclusions. My strongest advice would be that we not be hasty. There is no moral imperative upon us to approve something that will allow pluripotent stem cell research, and there is no reason for the almost agonized eagerness I sense among Hurlbut and his allies to find ethical routes to such research. I think that it will be much harder--both psychologically and sociologically--for pro-lifers to withdraw their approval once given to some procedure than to decide later that some research procedure they had questioned is in fact morally acceptable. I hope, in any event, to have provided sufficient information and framework for a consideration of ANT-OAR from a scientifically informed pro-life perspective.