Reflection on Dignitatis Personae
Reflection on Dignitatis Personae
Kevin L. Flannery, S.J.
Professor of Philosophy Pontifical Gregorian University
Possibilities and limitations of gene therapy
The three numbers of the instruction Dignitatis personae devoted to gene therapy (nn. 25-27) make a number of useful and important distinctions among ways of engaging in gene therapy, but they are especially interesting because of the principles of bioethics they presuppose and partially articulate.
As for the distinctions, in the first paragraph of n. 25, the Congregation for the Doctrine of the Faith acknowledges that the scope of the term "gene therapy" has expanded in recent years to comprise now not only hereditary but also non-hereditary diseases. Regarding the former, one example would be the cure of the disease that afflicted the famous "bubble boy", who was unable to develop an effective immune system and could only survive in a sealed atmosphere.
In a clinical trial, ten children received stem cells, derived from their own bone-marrow, that had been genetically engineered so that they now carried a normal copy of the gene that, when defective, causes the disease. Of the ten, nine gave evidence of long-term improvements in their immune response.
An example of a prospective cure of a non-hereditary disease would be the type of cure promised by successful experimentation on gastric cancer in mice. In results reported in October of this year, organisms ("vectors") containing viruses with a particular genetic make-up were made to infect gastric cancer cells, resulting in the slower growth of tumours.
Gene therapy can also be either "germ line cell therapy" (affecting gametes — eggs or sperm — or their immediate precursors) or "somatic cell gene therapy" (affecting parts of the body other than the gametes and not affecting the immediate subject's progeny). The two types of therapy already mentioned would count as somatic cell gene therapy.
From an ethical perspective, such therapy is relatively uncontroversial since, in itself, to cure a person of a disease is a good thing. Risks, however, are always involved, and these can have a bearing upon the morality of pursuing a particular cure. This is relevant when one considers that, in the case of the above mentioned children who received the genetically engineered bone-marrow-derived stem cells, Three years after the intervention, the two youngest developed leukaemia. The morality of germ line cell therapy — since it affects as yet non-existent persons — is a much more complicated matter; it will be treated below.
Either type of cell therapy, germ line or somatic, can be performed before or after birth. An example of a somatic therapy performed before birth would be the type of therapy promised by the recent successful in utero transfer of a gene which allows the production of functional hair cells in the inner ear of mice. Non-functional hair cells in the inner ear is the most frequent cause of hearing impairment.
Experiments with such in utero somatic gene therapies have raised fears that they could have inadvertent effects upon germ cell lines (that is, the germ cells passed on from generation to generation). Experimental results with respect to prenatal stem cell gene therapy are as yet scarce — even from experiments using animals. However, the fears of scientists and others that modifications to the somatic gene structures could influence germ cells already constitute a recognition that in utero germ cell therapy is both theoretically possible and problematic.
As already suggested, the prospect of germ line cell therapy — whether in utero or not — raises a plethora of ethical issues, and the treatment of these issues in Dignitatis personae presupposes philosophical principles located at the core of the Church's understanding of bioethics. Some of the ethical issues are not proper to germ line cell therapy itself but have to do rather with the destruction of — or risk to — embryos that would very likely be part of any experiments upon human germ line cells. The principles involved here are well known.
Moreover, even now the risks associated with genetic manipulation can have severe, uncontrolled or uncontrollable consequences for future generations. With good reason, then, Dignitatis personae says, "in its current state, germ line cell therapy in all its forms is morally illicit" (n. 26).
In the subsequent number, the document also says that germ line cell therapy for purposes "other than medical treatment," in which the aim is to improve and strengthen the gene pool "would promote a eugenic mentality and would lead to indirect social stigma with regard to those people who lack certain qualities, while privileging qualities that happen to be appreciated by a certain culture or society" (n. 27). Here one may ask what the principles presupposed by these statements are.
First of all, it needs to be acknowledged that the Church is not opposed to, in themselves, actions that will have future, supposedly favourable, effects upon germ cell lines. After all, she prohibits marriages between close relatives. At least part of the reason for this prohibition has to do with the negative genetic consequences of doing otherwise. In the encyclical letter Casti Connubii, Pius XI, while criticizing some who are "overly solicitous for the cause of eugenics," also acknowledges that it is "not contrary to right reason" to attempt to procure "the strength and health of the future child" (n. 68).
Similarly, in a discourse to the World Medical Association on October 29th, 1983, John Paul II issues a stern warning about what he calls "genetic manipulation" but also acknowledges that "a strictly therapeutic intervention whose explict objective is the healing of various maladies such as those stemming from chromosomal defects will, in principle, be considered desirable, provided it is directed to the true promotion of the personal well-being of the individual without doing harm to his integrity or worsening his conditions of life" (n. 28).
The Holy Father goes on in the same talk to commend those who prefer over 'genetic manipulation' the term "'genetic surgery' so as better to indicate that the doctor intervenes not in order to modify nature but in order to help it to "develop and flourish in its own line: that of creation, that willed by God" (ibid.).
So, if the Church is not opposed to genetic intervention itself, what is the basis of its negative statements in Dignitatis personae regarding germ line cell therapy, and in particular its statement about germ line cell therapy for purposes other than medical treatment? An answer is suggested by the words of John Paul II just quoted. The difference between legitimate and illegitimate means of effecting genetic change is that the legitimate practices cure diseases, the illegitimate ones do not.
This approach gains support from John Paul II's invocation, earlier in the same talk, of the Hippocratic Oath. The original (fifth century B.C.) formulation of that oath speaks throughout of a doctor's relationship with the ill or the distressed (kamnontes). The oath would seem, therefore, to understand medicine as the curing of diseases.
With this understanding in mind, the Church and those who teach in her name are capable of distinguishing good gene therapy from bad. Gene therapy is to be rejected when it is not for the sake of health, the definition of which is fixed by God and not by man. Gene therapy operates outside this definition in a very obvious way when it involves the destruction of human embryos, for such destruction does not protect or promote their health. But it does the same when, from among the possible characteristics of healthy human beings, it selects certain ones as preferable and attempts to bring into existence persons with those characteristics.
The concern of such procedures is clearly not to promote health by combating disease, for they begin by selecting from a pool of possible future healthy persons, certain of them with characteristics that, in the words of Dignitatis personae n. 27, "happen to be appreciated by a certain culture or society." The end of such procedures is clearly not health, which the whole pool of possible future persons is presupposed to possess, but the favoured characteristics.
By favouring certain human characteristics as distinct from human nature itself and the health pertaining to it, such procedures betray a lack of respect for humanity and for human persons themselves. To repeat the crucial words of Dignitatis personae, "such manipulation would promote a eugenic mentality and would lead to indirect social stigma with regard to those people who lack certain qualities, while privileging qualities that happen to be appreciated by a certain culture or society.... In the attempt to create a new type of human being one can recognize an ideological element in which man tries to take the place of his Creator" (n. 27).
Weekly Edition in English
6 May 2009, page 13
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