Tuesday, June 24, 2008

Secrets of Embryology

On dirty little secrets and the choice of words. Facts: Every human being begins as a single-cell zygote, grows through the embryonic stage, then the fetal stage, is born and develops through infancy, through childhood, and through adulthood, until death. Each human being is genetically the same human being at every stage, despite changes in his or her appearance.

Embryologists are united on this point. Consider the following statements from standard textbooks: “Human development begins at fertilization . . . This highly specialized, totipotent cell marked the beginning of each of us as a unique individual” (Keith L. Moore and T.V.N. Persaud); “Almost all higher animals start their lives from a single cell, the fertilized ovum (zygote) . . . The time of fertilization represents the starting point in the life history, or ontogeny, of the individual” (Bruce M. Carlson); “Although life is a continuous process, fertilization is a critical landmark because, under ordinary circumstances, a new, genetically distinct human organism is thereby formed . . . The embryo now exists as a genetic unity” (Ronan O’Rahilly and Faiola Muller).

Whether the new organism is produced by fertilization or by cloning, each new human organism is a distinct entity. Twins are genetic duplicates of each other, but no one would deny that each is a distinct human individual. Similarly, a clone would be a genetic duplicate of another human being, but there is no denying that it would also be a separate individual.

From its first moment, supplied with its complete set of chromosomes, each new zygote directs its own integral functioning and development. It proceeds, unless death intervenes, through every stage of human development until one day it reaches the adult stage. It will grow and it will develop and it will change its appearance, but it will never undergo a change in its basic nature. It will never grow up to be a cow or a fish. It is a human being from the first moment of its existence. As Paul Ramsey has noted, “The embryo’s subsequent development may be described as a process of becoming what he already is from the moment of conception.”

These are the facts, which we can either affirm or deny. Unfortunately, the denial of inconvenient facts has become quite common during the past several decades. Consider, for example, an editorial published in the September 1970 issue of California Medicine, which was then the journal of the California Medical Association. The editorial invited the Association’s members to play a new game called “semantic gymnastics.” The first rule of the game was the “avoidance of the scientific fact, which everyone really knows, that human life begins at conception and is continuous whether intra- or extra-uterine until death.” The goal was to replace “the traditional Western ethic” respecting “the intrinsic worth and equal value of every human life regardless of its state or condition” with “a new ethic for medicine and society” in order “to separate the idea of abortion from the idea of killing.”

In subsequent years, the dehumanization of the unborn was taken a step further when the concept of the “pre-embryo” was advanced. The term referred to the embryo before its implantation in the womb. Certainly the embryo at this point is “pre-implantation,” and certainly implantation is a highly significant event. If the embryo does not implant, it will die; if it implants, it will receive nutrition and a suitable environment in which to live, grow, and develop. (Every human being at every stage of life similarly requires nutrition and a suitable environment.) But the critical question is: Does implantation effect a change in the nature of the thing that implants? It is clear from basic facts of embryology that it does not. In the 2001 edition of his leading textbook on embryology, Ronan O’Rahilly (an "undisputed authority on human embryology") writes, “The term ‘pre-embryo’ is not used here [because] . . . it may convey the erroneous idea that a new human organism is formed only at some considerable time after fertilization. [The term] was introduced in 1986 largely for public policy reasons.”

For what public policy reasons was the term “pre-embryo” invented? Princeton biology professor Lee Silver, a noted advocate of all the new biotechnologies, supplies the answer in his Remaking Eden (1997):
I’ll let you in on a secret. The term pre-embryo has been embraced wholeheartedly by IVF practitioners for reasons that are political, not scientific. The new term is used to provide the illusion that there is something profoundly different between a six-day-old embryo and a sixteen-day-old embryo. The term is useful in the political arena—where decisions are made about whether to allow early embryo experimentation—as well as in the confines of a doctor’s office where it can be used to allay moral concerns that might be expressed by IVF patients.
As Gilbert Meilaender has noted, the “pre-embryo” is merely the unimplanted embryo. In other words, it is already an embryo, and all embryos are, at first, unimplanted. An embryo subsequently implants unless something (or someone) interferes or the embryo is defective. Its life is continuous from its first moment (whether through fertilization or through cloning) until death. The term “pre-embryo” was developed and used largely, if not exclusively, to mislead: to hide scientific facts about the beginnings and unity of human life; to bolster support for a new reproductive technology; and to obtain funding for experiments on human embryos. It has led to a confused jurisprudence that treats the embryo, in certain contexts, more like property than like a human being.


Regina said...

Great article. I couldn't stop reading. Maybe I should send this to my sister.

Regina said...

One more comment:

Speaking of clones, my sister - as of two weeks ago - was seriously suggesting that clones should be farmed to experiment on - especially pregnant clones so that we "real humans" might further our knowledge on what the pregnant body and fetus can tolerate. The conversation made me want to vomit all over her. Ask me more about this.