from species‐typical traits, does it follow that we may perform genetic interventions to treat diseases but not to enhance otherwise healthy people? Since we regard the concept of disease as descriptive, we cannot answer this question without making some normative assumptions. Saying that someone has a disease is like saying that he or she has red hair, is five feet tall, or was born in New York City. These descriptions of that person carry no normative import. Hence the descriptive account of disease, by itself, does not provide us with a way of drawing a solid moral line between therapy and enhancement. For this approach to disease to draw moral boundaries between therapy and enhancement, it needs to be supplemented by a normatively rich account of the rightness of therapy and wrongness of enhancement.
Perhaps the normative approach fares better than the descriptive one. If we accept this view, it follows that therapy has some positive moral value, since therapy is an attempt to treat diseases, which are defined as traits or abilities that do not fall within social or cultural norms. If it is “bad” to have a disease, then we are morally justified in performing interventions that attempt to treat or prevent diseases, since these procedures impart “good” states of being. Thus this normative approach implies that therapy is morally right. But does it imply that enhancement is morally wrong? The answer to this question depends, in large part, on the scope of the concepts of health and disease. If we hold that the concept of health defines a set of traits and abilities that should be possessed by all members of society and that any deviations are diseases, then any intervention that results in a deviation from these norms would be viewed as immoral. Hence, enhancement would be inherently immoral. But this account of health and disease is way too broad; there must be some morally neutral traits and abilities. If there are no morally neutral traits and abilities, then any person that deviates from health norms is “sick.” This view would leave very little room for individual variation, to say nothing of the freedom to choose to deviate from health norms. If we accept a narrower account of health and disease, then we will open up some room for morally acceptable deviations from health norms. But this interpretation implies that enhancement interventions could be morally acceptable, provided that they do not violate other moral norms, such as nonmaleficence, autonomy, utility, and so on. Enhancement would not be inherently wrong, on this view, but the rightness or wrongness of any enhancement procedure would depend on its various factual and normative aspects.
The upshot of this discussion is that neither of the two main approaches to health and disease provides us with solid moral boundaries between genetic enhancement and genetic therapy. One might suggest that we examine alternative approaches, but I doubt that other, more refined theories of health and disease will provide us with a way of drawing sharp moral boundaries between genetic enhancement and genetic therapy. Perhaps we should look at other ways of endowing the distinction with moral significance.
The Goals of Medicine
A slightly different approach to these issues asserts that genetic therapy is on solid moral ground because it promotes the goals of medicine, while genetic enhancement promotes other, morally questionable goals. But what are the goals of medicine? This is not an easy question to answer, since medicine seems to serve a variety of purposes, such as the treatment of disease, the prevention of disease, the promotion of human health and well‐being, and the relief of suffering. Many of the so‐called goals of medicine, such as the prevention of disease and the promotion of human health, may also be promoted by procedures that we would classify as forms of enhancement.45 For example, some writers have suggested that we might be able to perform genetic interventions that enhance the human immune system by making it better able to fight diseases, including cancer.46 Most people would accept the idea that providing children with immunizations against the measles, mumps, and rubella promotes the goals of medicine. If we accept the notion that ordinary, nongenetic enhancement of the immune system promotes the goals of medicine, then shouldn’t we also agree that genetic enhancements of the immune system serve the same goals? And what about other forms of healthcare, such as rhinoplasty, liposuction, orthodontics, breast augmentation, hair removal, and hair transplants? If these cosmetic procedures serve medical goals, then cosmetic uses of genetic technology, such as somatic gene therapy for baldness, and germline gene therapy for straight teeth, would also seem to serve medical goals. Finally, consider the procedures that are designed to relieve suffering, such as pain control and anesthesia. If we can develop drugs to promote these goals, then why not develop genetic procedures to meet similar objectives? It is not beyond the realm of possibility that we could use genetic therapy to induce the body to produce endorphins. Many forms of enhancement may serve medical goals. Once again, the therapy–enhancement distinction appears not to set any firm moral boundaries in genetic medicine.
One might attempt to avoid this problem by narrowly construing the goals of medicine: the goals of medicine are to treat and prevent diseases in human beings. Other uses of medical technology do not serve the goals of medicine. There are two problems with this response. First, it assumes that we agree on the goals of medicine and the definitions of health and disease. Second, even if we could agree that medicine’s goals are to treat and prevent diseases and we can define “health” and “disease,” why would it be immoral to use medical technology and science for nonmedical purposes? If a medical procedure, such as mastectomy, is developed for therapeutic purposes, what is wrong with using that procedure for “nonmedical” purposes, such as breast reduction surgery in men with overdeveloped breasts? Admittedly, there are many morally troubling nonmedical uses of medical science and technology, such as the use of steroids by athletes and the use of laxatives by anorexics, but these morally troubling uses of medicine are morally troubling because they violate various moral principles or values, such as fairness and nonmaleficence, not because they are nonmedical uses of medicine.
One might argue that those who use medical science and technology for nonmedical purposes violate medicine’s professional norms, but this point only applies to those who consider themselves to be medical professionals. If a procedure violates medical norms, it is medically unethical, but this does not mean that the procedure is unethical outside of the context of medical care. For example, the American Medical Association holds that it is unethical for physicians to assist the state in executions, but this policy does not constitute an unconditional argument against capital punishment. To make the case against capital punishment, one must appeal to wider moral and political norms. Hence the goals of medicine also do not set a morally sharp dividing line between genetic therapy and enhancement.
Our Humanness
One might try to draw moral boundaries between genetic therapy and genetic enhancement by arguing that genetic enhancement is inherently immoral because it changes the human form. Genetic therapy only attempts to restore or safeguard our humanness, while enhancement changes those very features that make us human. Although GLGE and GLGT can more profoundly change human traits than SGE and SGT, both technologies can alter our humanness (or our humanity). To explore these issues in depth, we need to answer two questions: (1) What traits or abilities make us human? and (2) Why would it be wrong to change those traits or abilities? Philosophers have proposed answers to the first question ever since Aristotle defined man as “the rational animal.” A thorough answer to the question of defining our humanness takes us way beyond the scope of this essay, but I will offer the reader a brief perspective.47
If we have learned anything from the abortion debate, we have learned that it is not at all easy to specify necessary and sufficient conditions for a thing to be human. Humanness is best understood as a cluster concept in that it can be equated with a list of characteristics but not with a set of necessary and sufficient conditions.48 Some of these characteristics include:
1 physical traits and abilities, such as an opposable thumb, bipedalism, etc.
2 psychosocial
