Pros And Cons Of Human Germline Gene Therapy

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MJM 1997 3: 126-132

Copyright © 1997 by MJM

CROSSROADS: WHERE MEDICINE AND THE HUMANITIES MEET

Human Germline Gene Therapy
Torsten O. Nielsen*, M.D.C.M., Ph.D.

1

The idea of human germline gene therapy introducing genetic changes into early embryos which become incorporated into all cells of the body and, as such, are passed on to future generations - has elicited considerable ethical, scientific, and political controversy. Technological advances have turned what until recently was fanciful science fiction into a theoretical and practical possibility. Human germline interventions raise unique ethical concerns which must be addressed, such as its possible use for eugenics. The basic technology of germline gene therapy
In response, it has been argued that germline genetic alterations are unlike classical eugenics, in that they eliminate defective genes rather than human beings (12), and that multifactorial traits like intelligence or attractiveness may never prove amenable to manipulation. More importantly, the eugenics argument presupposes a slippery slope, however, morally-relevant lines can be drawn to delineate acceptable versus unethical applications of the technology (16). To this end, Berger and Gert (6) define the term “malady” as a physical disorder which provides a direct challenge to the fundamental principles of benevolence and nonmaleficence, by imposing the universally-accepted evils of death, pain, or disability, precluding the freedom and pleasure available in life to the vast majority of other human beings. Relief of morbidity and mortality fall within the acceptable line, changing sex or increasing otherwise normal intelligence or height — decisions not based on medical need — would lie outside. Thus, the ethical line should be drawn to make therapy acceptable and enhancement unacceptable, rather than the current state permitting somatic manipulations but disallowing germline experiments (16). Informed consent becomes a special problem with germline gene therapy, because it is impossible to obtain the
New protocols are approved only when they make relatively cautious, small extensions to existing procedures (12). Such bodies may well be effective in preventing the mistakes of the past, where unapproved attempts were made on patients whose consent was not clear. But limits may not work in the private sector, or across international boundaries. Exciting new technology tends to get used, even when inappropriate, despite better alternatives being available, and risks that are not fully assessed and likely underestimated (6). If human germline gene therapy techniques ever became available, the possibility remains that their use could not be constrained within a moral line allowing only therapeutic corrections of severe genetic maladies. While rarely exploring, in depth, the detailed technological limitations of the procedure, government commissions in many first world countries have opposed research into human germline gene therapy (17). For example, the Canadian Royal Commission on New Reproductive Technologies proposed a blanket ban on both somatic cell enhancement interventions and on all germline alterations, therapeutic or otherwise (5). In fact, legislation is not needed at this point, because a de facto ban on human germline interventions is already in place, as there remain far too many technical