Possibilities and limitations of gene
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"
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
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
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
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
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
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"