Embyon est-il déjà un être humain ? La réponse appartient-elle à la science ?

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ROME, APRIL 13, 2008 (Zenit.org).- Stem cell research using material taken from human embryos continues to be hotly debated. Advocates of using embryos maintain that at such early stages, the cells cannot be considered a human person. However, a recent book by two philosophers argues the contrary.

Robert P. George, who is also a member of the President's Council on Bioethics, and Christopher Tollefsen, avoid religious-based arguments and lay out a series of scientific and philosophical principles in favor of the human status of the embryo. In "Embryo: A Defense of Human Life" (Doubleday), they maintain that the status of a human being commences at the moment of conception.

The book starts by recounting the history of a boy named Noah, born in January 2007. He was rescued, along with other frozen embryos, from the disaster that struck New Orleans in 2005. It was Noah's life -- a human life -- that was saved, George and Tollefsen point out, the same life that was later implanted in a womb and was subsequently born.

A human embryo, they continue, is a living member of the human species even at the earliest stage of development. It is not some type of other animal organism, or some kind of a clump of cells that later undergoes a radical transformation. Barring some kind of tragic accident, a being in the embryonic stage will proceed to the fetal stage and continue to progress in this development.

The point at issue, according to the authors, is at what stage we can identify a single biological system that has started on the process to being a mature human being. This decisive moment, they argue, comes with conception. Some medical experts believe it happens slightly after, with the formation of the united chromosomes of the sperm and egg. In any case, continue George and Tollefsen, there is widespread agreement among embryologists that at the latest, a new human individual comes into existence once the chromosomal structure is formed.

They argue that there are three key points to keep in mind regarding the human status of the embryo.

-- From the start, it is distinct from any cell of the mother or the father.

-- It is human in its genetic makeup.

-- It is a complete organism, though immature, and unless prevented by disease or violence, will develop into the mature stage of a human being.

Consequently, destroying human embryos, even at an early stage, in order to obtain stem cells for research or medical treatment is giving a license to kill a certain class of human beings in order to benefit others.

Not just science

Faced with such a situation, George and Tollefsen reject the position that it should be scientists who alone determine what they do in their research activities. The problem with the embryonic stem cell issue is that the pace of technology has run ahead of a discussion about the nature and value of human embryos, the authors contend.

Opposing such research does not place us in a classic sort of science versus religion situation, they affirm. Opposing the destruction of human life in its initial stages does not have to rely on religious principles, or on believing that such a life has been endowed with a soul, the book adds.

Purely philosophical reason is sufficient to guide us in determining what is ethically licit to do with human embryos. In this sense, defending the rights of an embryo is similar to defending people against unjust discrimination, argue George and Tollefsen.

They admit there are differing moral philosophies. One theory to discard is that of consequentialism, which leads us to the position that there are some human beings who must be sacrificed for the greater good.

George and Tollefsen found their ethical position on natural law theory, which leads to the conclusuion that it is morally wrong to damage or destroy a basic human good. If, therefore, a scientist were to seek a cure for some disease, but the method involved deliberately destroys human life, then it is not licit.


The one basic human right, in fact, that almost all natural law theorists agree upon is that of an innocent person not to be directly killed or maimed. The capacity of the human being to reason and choose freely sets us apart and gives us a dignity higher than other living beings. An assault on human life is, consequently, an assault on human dignity, no matter the victim's age or stage of development, the authors conclude.


One of the book's chapters deals with the objection that while an embryo may be human it is, nonetheless, not a person and does not have the same dignity or rights. George and Tollefsen reply that such a view is mistaken, as it falls into the error of considering that some human beings are inferior to others on the basis of accidental characteristics.

In fact, they continue, denying the status of personhood based on a capacity for mental capacities or other parameters of functionality poses many problems. Are we to be allowed to kill newborn babies, given that they too are unable to carry out basic human functions?

Rather, we should realize that a mere quantitative difference in capacity is not the correct criterion for determining rights, as it is only a difference of degree. The real difference is between human beings and all other non-human animals, which is a radical difference of kind. Thus, the embryo is a potential adult in the same way that infants, children and adolescents are potential adults.

Embryos are, they insist, already human beings, and are not merely potentially human. Moreover, the right to life of a human does not vary according to the stage of its development because it is the foundational right for persons. "It is the right on which all other rights are predicated, and marks whether a being is a being of moral standing at all," continue George and Tollefsen.


Another fallacious argument is that which maintains that embryos are not worthy of a full moral status because a high percentage of them fail to implant in the mother's womb or spontaneously abort. The authors point out that this is a naturalistic fallacy, supposing that what happens in nature must be morally acceptable when caused by human action.

The falsity of this reasoning is also evident, George and Tollefsen point out, when you consider that historically, infant mortality has been very high. In such a situation just because many young babies died does not make it ethically licit for them to be killed to benefit others.

Another line of reasoning used to defend research with embryonic cells is that there are many thousands of frozen embryos who remain unwanted following artificial fertilization treatments, and who will never have a chance to be implanted and grow to maturity. A scientist could use these cells for the good of research.

George and Tollefsen reply, saying that this it is manifestly unfair to demand that a person -- in this case the embryo -- sacrifice his life in this manner. "Human beings have a moral right not to be intentionally killed to benefit others," they declare.

They also argue that it is an error to condemn hundreds of thousands of human lives to a sort of frozen limbo. Thus the process of creating and freezing such embryos needs to questioned, state the authors. We need to turn our attention to their fate, George and Tollesen recommend, not by using embryos as if they were some kind of biological material, but by acknowledging their humanity. These and other persuasive arguments in the book make it valuable reading at a time when science is at danger of running ahead of our ethical reasoning.

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