Who or What is the Preembryo?

Introduction

Although widely used by scientists, the term "preembryo" has raised some suspicions. Histopathologist Michael Jarmulowicz (1990), for example, asserts that the term was adopted by the American Fertility Society (AFS) and the Voluntary Licensing Authority (VLA) in Britain "as an exercise of linguistic engineering to make human embryo research more palatable to the general public."

I cannot speak for the VLA, but I can clarify that this was not the motive of the AFS. As a member of the AFS ethics committee that discussed and adopted this terminology, I know that our discussion was not tied to embryo research or moral issues. The term "preembryo" was adopted because the earliest stages of mammalian development primarily involve establishment of the nonembryonic trophoblast, rather than the formation of the embryo. As Clifford Grobstein (1988, p. 61), a distinguished basic scientist who also sat on the AFS committee notes:

The scientific rationale for the term preembryo . . . is its greater accuracy in characterizing the initial phase of mammalian and human development. . . . The status implications of such a change in terminology were not at issue in the discussion.

This is not to say that the moral status of the preembryo is not a concern worthy of independent consideration. It is an important question with significant practical implications, especially in the context of in vitro fertilization. At stake are issues such as: (1) what may be done to preembryos before transfer; (2) whether all preembryos must be transferred; and (3) what may be done to preembryos that are not transferred (Ethics Committee of the American Fertility Society (AFS) 1986, p. 29S). Furthermore, emergency treatment of rape cases may also depend on such a determination.

Cryopreservation, which entails freezing unused preembryos for possible later use, is one example of a procedure that raises issues associated with the moral status of the preembryo. Cryopreservation decreases the number of stimulated egg recovery cycles a woman must undergo and increases flexibility in transfer protocols. But thawing of the preembryos is not a completely benign process; significant numbers of the preembryos die in the process and injury cannot be excluded.

In addition, down the road a year or so lies preimplantation genetic diagnosis, now being tested in several centers of reproductive research. This would involve the removal of one or more cells from a preembryo developing in vitro. The DNA from these cells would be studied and then only genetically normal preembryos would be transferred. With the growth in knowledge about single gene defects and the rapid advance of amplification technology, which allows gene visualization, it is not difficult to imagine scientists embarking on a variety of micromanipulations of the preembryo for the sake of gaining knowledge.

Not all research with gametes involves preembryos, but clearly some experiments and procedures await resolution of the moral status of the preembryo. I contend in this paper that the moral status—and specifically the controversial issue of personhood—is related to attainment of developmental individuality (being the source of one individual). This contrasts with the view that holds that personhood occurs earlier, at the point of genetic uniqueness. I believe that an embryo that has developed to the point where it can be one individual and one individual only, differs in moral status from a preembryo that has not, even if in many cases we may choose to treat them similarly.

The Scientific Underpinnings

Two things must be kept in mind—and in a sense, in tension—in turning to science for help in assessing the status of the preembryo. First, science is not competent to decide the question of personhood or ensoulment. As the Catholic document, Declaration on Procured Abortion, which I will return to later, notes: "It is a philosophical problem" (Congregation for the Doctrine of the Faith (CDF) 1974, p. 10, endnote 19). On the other hand, another Catholic document, Donum vitae(CDF 1987), notes that the conclusions of science provide a "valuable indication" for reason's deliberations about personhood. We might say that if science cannot decide the question of personhood, neither can it be decided without science.

For my review of embryological science...