The argument is somewhat common, but it simply doesn't work. First, the estimates often cited of the percentage of embryos who die naturally are probably much too high. Many early "miscarriages" appear to involve the product of a faulty fertilization, such as a complete hydatidiform mole (a kind of disordered growth), rather than a new embryonic organism. In such cases, no actual human embryos are lost. (George and Tollefsen cite embryology textbooks to support this claim on p. 137 of Embryo.)Second, regardless of how many embryos die from miscarriage, that fact does not justify abortion or embryo-destructive research. It does not follow that if some unborn human beings die by natural causes, it is therefore permissible to ourselves intentionally cause the death of unborn human beings. For example, the fact that a natural disaster, such as an earthquake, claims the lives of thousands of people does not justify a massacre. The fact that my father could die from a heart attack at any moment does not justify his murder.
Indeed, the reality of miscarriage simply has no bearing on the moral status of human embryos (i.e., how they ought to be treated), just as the reality of high infant mortality throughout most of human history (probably higher than today's rate of miscarriage) had no bearing on the moral status of infants. Nor does the high rate of death from AIDS in Africa call into question the worth and dignity of those affected by that terrible disease. In fact, as Francis Beckwith points out, a full 100 percent of people die at some point in time, but they are people nonetheless, and ought to be treated as such.
Third, VerBruggen and some others say that if pro-lifers really believed that embryos are valuable human beings, they would promote research to find ways to prevent early miscarriage. But at best this shows that pro-lifers are inconsistent; it does nothing to refute the pro-life position that human embryos deserve full moral respect. Moreover, society does try to stop miscarriage insofar as it might be possible. Yuval Levin notes:
A great deal of medical research (much of it funded by the NIH these days) has also gone into better understanding the causes of early miscarriages and finding ways to prevent them. Almost all early embryo deaths happen before the mother even knows she's pregnant, so it wouldn't really be possible to do much to prevent them, but those that occur later are very often found deeply regrettable by the families involved, to put it mildly, and a huge amount of effort and money are spent (by individuals and by our society as a whole) trying to prevent them.In addition, natural death is morally different than unjust killing, and our obligations to prevent unjust killing may not be equivalent to our obligations pertaining to natural death. As Beckwith writes, VerBruggen's argument "confuses our obvious prima facie moral obligation not to commit homicide (that is, to intentionally kill an innocent human person) with the questionable moral obligation to interfere with natural death of a human person in every instance." Christopher Kaczor adds:
Just as there is no moral requirement to make extraordinary efforts to attempt to restore health to elderly human beings, we need not make extraordinary efforts to attempt to restore health to human beings in their embryonic state. An affirmation of the dignity of all human life simply does not imply that one must always make every effort to save every human life, regardless of the burdens involved or the likelihood of success. Even though every human life has intrinsic value ... it does not follow that every proposed treatment is worthwhile or valuable. ...So it seems clear that the pro-life movement is not acting inconsistently. Regardless, defenders of abortion and embryo-destructive research will have to do the hard work of actually showing that embryonic human beings do not merit basic moral respect and thus may be killed for the convenience or theoretical benefit of others. Appealing to miscarriage does absolutely nothing to support their view.
If we did [emphasis added] know exactly who was going to have a miscarriage and when, and if we had effective and nonburdensome ways to save this endangered life [we obviously do not currently], then the pro-life view would entail that we would have a prima facie obligation to try to save the human being in utero, and indeed a great many people would vigorously try to do this—including many people who suffer from infertility problems.
