What are we to think about the fact that Nature (and for believers, Nature's God) profligately creates and destroys human embryos? John Opitz, a professor of pediatrics, human genetics, and obstetrics and gynecology at the University of Utah, testified before the President's Council on Bioethics that between 60 and 80 percent of all naturally conceived embryos are simply flushed out in women's normal menstrual flows unnoticed. This is not miscarriage we're talking about. The women and their husbands or partners never even know that conception has taken place; the embryos disappear from their wombs in their menstrual flows. In fact, according to Opitz, embryologists estimate that the rate of natural loss for embryos that have developed for seven days or more is 60 percent. The total rate of natural loss of human embryos increases to at least 80 percent if one counts from the moment of conception. About half of the embryos lost are abnormal, but half are not, and had they implanted they would probably have developed into healthy babies.
So millions of viable human embryos each year produced via normal conception fail to implant and never develop further. Does this mean America is suffering a veritable holocaust of innocent human life annihilated? Consider the claim made by right-to-life apologists like Robert George, a Princeton University professor of jurisprudence and a member of the President's Council on Bioethics, that every embryo is "already a human being." Does that mean that if we could detect such unimplanted embryos as they leave the womb, we would have a duty to rescue them and try to implant them anyway?
"If the embryo loss that accompanies natural procreation were the moral equivalent of infant death, then pregnancy would have to be regarded as a public health crisis of epidemic proportions: Alleviating natural embryo loss would be a more urgent moral cause than abortion, in vitro fertilization, and stem-cell research combined," declared Michael Sandel, a Harvard University government professor, also a member of the President's Council on Bioethics.
As far as I know, bioconservatives like Robert George do not advocate the rescue of naturally conceived unimplanted embryos. But why not? In right-to-life terms, normal unimplanted embryos are the moral equivalents of a 30-year-old mother of three children.
Of course, culturally we do not mourn the deaths of these millions of embryos as we would the death of a child—and reasonably so, because we do in fact know that these embryos are not people. Try this thought experiment. A fire breaks out in a fertility clinic and you have a choice: You can save a three-year-old child or a Petri dish containing 10 seven-day old embryos. Which do you choose to rescue?
Stepping onto dangerous theological ground, it seems that if human embryos consisting of one hundred cells or less are the moral equivalents of a normal adult, then religious believers must accept that such embryos share all of the attributes of a human being, including the possession of an immortal soul. So even if we generously exclude all of the naturally conceived abnormal embryos—presuming, for the sake of theological argument, that imperfections in their gene expression have somehow blocked the installation of a soul—that would still mean that perhaps 40 percent of all the residents of Heaven were never born, never developed brains, and never had thoughts, emotions, experiences, hopes, dreams, or desires.
Yet millions of intelligent people of good will maintain that seven-day-old embryos have the exact same moral standing as do readers of this column. Acting on this sincere belief, they are trying to block biomedical research on human embryonic stem cells that is desired by millions of their fellow citizens.
But there may be a way out of this politico-theological impasse. The President's Council on Bioethics held an extraordinarily interesting session earlier this month in which two different avenues for obtaining human embryonic stem cells were proposed, in ways that would skirt right-to-life moral objections.
First, Howard Zucker and Donald Landry, two medical professors at Columbia University, proposed "a new definition of death for the human organism, an organism in development, and that is the irreversible arrest of cell division." They pointed out that a good percentage of in-vitro fertilized (IVF) embryos consist of a mixture of cells, some containing the wrong number of chromosomes (aneuploidy), some with the normal number. Embryos with such cell mixtures often cease development by cell division and thus cannot develop into fetuses, much less babies. Zucker and Landry argue that such embryos can be considered dead, and the normal embryonic cells they contain can be harvested just as organs can be ethically harvested from brain-dead adults. (Animal experiments have already shown that cells harvested from defective embryos will produce normal tissues.) Thus, we get stem cells from an entity that could not, under any circumstances, have become a human being.
William Hurlbut, a consulting professor in the Program of Human Biology at Stanford University and another member of the President's Council on Bioethics, proposed another way to produce cloned human embryonic stem cells that right-to-lifers should not find morally objectionable. Hurlbut cited work by researcher Janet Rossant at Mount Sinai Hospital in Toronto in which she inactivated the cdx2 gene in mice. Once the cdx2 gene is inactivated, the mouse embryo cannot form a trophoblast—the tissues that grow into the placenta. However, embryonic stem cells do develop, although they cannot form an embryo. Hurlbut proposed an attempt to find similar genes that could be inactivated in the nuclei of adult human cells before they are installed in enucleated human eggs to produce cloned embryonic stem cells that are a genetic match for the person who donates the adult nucleus. (Transplanted cells and tissues produced by such therapeutic cloning would not be rejected by the donor's immune system.) Once the stem cells have been derived, the inactivated genes could be reactivated so that the stem cells could be used to produce normal transplantable cells and tissues.
"This process does not involve the creation of an embryo that is then altered to transform it into a non-embryonic entity," explained Hurlbut. "Rather the proposed genetic alteration is accomplished ab initio, the entity is brought into existence with a genetic structure insufficient to generate a human embryo."
Will this research reduce the number of embryos populating heaven? Who knows? But these options offer a possible way around the moral blockades that impede promising biomedical research on human embryonic stem cells. Should we halt current human embryonic stem-cell research while these possible new avenues of research are being explored? Absolutely not. That would be surrendering to the moral bullying of a minority that wants to halt promising medical research that could cure millions on theological grounds that many of their fellow citizens do not share.