Читать книгу Bioethics - Группа авторов - Страница 58

There is always some possibility that reproduction will result in a child with a serious disease or handicap. Genetic counselors can help individuals determine whether they are at unusual risk and, as the Human Genome Project rolls on, their knowledge will increase by quantum leaps. As this knowledge becomes available, I believe we ought to use it to determine whether possible children are at risk before they are conceived.

In this chapter I want to defend the thesis that it is morally wrong to reproduce when we know there is a high risk of transmitting a serious disease or defect. This thesis holds that some reproductive acts are wrong, and my argument puts the burden of proof on those who disagree with it to show why its conclusions can be overridden. Hence it denies that people should be free to reproduce mindless of the consequences.³ However, as moral argument, it should be taken as a proposal for further debate and discussion. It is not, by itself, an argument in favor of legal prohibitions of reproduction.⁴

There is a huge range of genetic diseases. Some are quickly lethal; others kill more slowly, if at all. Some are mainly physical, some mainly mental; others impair both kinds of function. Some interfere tremendously with normal functioning, others less. Some are painful, some are not. There seems to be considerable agreement that rapidly lethal diseases, especially those, such as Tay‐Sachs, accompanied by painful deterioration, should be prevented even at the cost of abortion. Conversely, there seems to be substantial agreement that relatively trivial problems, especially cosmetic ones, would not be legitimate grounds for abortion.⁵ In short, there are cases ranging from low risk of mild disease or disability to high risk of serious disease or disability. Although it is difficult to decide where the duty to refrain from procreation becomes compelling, I believe that there are some clear cases. I have chosen to focus on Huntington’s Disease to illustrate the kinds of concrete issues such decisions entail. However, the arguments are also relevant to many other genetic diseases.⁶

The symptoms of Huntington’s Disease usually begin between the ages of 30 and 50:

Onset is insidious. Personality changes (obstinacy, moodiness, lack of initiative) frequently antedate or accompany the involuntary choreic movements. These usually appear first in the face, neck, and arms, and are jerky, irregular, and stretching in character. Contradictions of the facial muscles result in grimaces; those of the respiratory muscles, lips, and tongue lead to hesitating, explosive speech. Irregular movements of the trunk are present; the gait is shuffling and dancing. Tendon reflexes are increased…Some patients display a fatuous euphoria; others are spiteful, irascible, destructive, and violent. Paranoid reactions are common. Poverty of thought and impairment of attention, memory, and judgment occur. As the disease progresses, walking becomes impossible, swallowing difficult, and dementia profound. Suicide is not uncommon.⁷

The illness lasts about fifteen years, terminating in death.

Huntington’s Disease is an autosomal dominant disease, meaning it is caused by a single defective gene located on a non‐sex chromosome. It is passed from one generation to the next via affected individuals. Each child of such an affected person has a 50 percent risk of inheriting the gene and thus of eventually developing the disease, even if he or she was born before the parent’s disease was evident.⁸

Until recently, Huntington’s Disease was especially problematic because most affected individuals did not know whether they had the gene for the disease until well into their child‐bearing years. So they had to decide about child‐bearing before knowing whether they could transmit the disease or not. If, in time, they did not develop symptoms of the disease, then their children could know they were not at risk for the disease. If unfortunately they did develop symptoms, then each of their children could know there was a 50 percent chance that they too had inherited the gene. In both cases, the children faced a period of prolonged anxiety as to whether they would develop the disease. Then, in the 1980s, thanks in part to an energetic campaign by Nancy Wexler, a genetic marker was found that, in certain circumstances, could tell people with a relatively high degree of probability whether or not they had the gene for the disease.⁹ Finally, in March 1993, the defective gene itself was discovered.¹⁰ Now individuals can find out whether they carry the gene for the disease, and prenatal screening can tell us whether a given fetus has inherited it. These technological developments change the moral scene substantially.

How serious are the risks involved in Huntington’s Disease? Geneticists often think a 10 percent risk is high.¹¹ But risk assessment also depends on what is at stake: the worse the possible outcome, the more undesirable an otherwise small risk seems. In medicine, as elsewhere, people may regard the same result quite differently. But for devastating diseases such as Huntington’s this part of the judgment should be unproblematic: no one wants a loved one to suffer in this way.¹²

There may still be considerable disagreement about the acceptability of a given risk. So it would be difficult in many circumstances to say how we should respond to a particular risk. Nevertheless, there are good grounds for a conservative approach, for it is reasonable to take special precautions to avoid very bad consequences, even if the risk is small. But the possible consequences here are very bad: a child who may inherit Huntington’s Disease has a much greater than average chance of being subjected to severe and prolonged suffering. And it is one thing to risk one’s own welfare, but quite another to do so for others and without their consent.

Is this judgment about Huntington’s Disease really defensible? People appear to have quite different opinions. Optimists argue that a child born into a family afflicted with Huntington’s Disease has a reasonable chance of living a satisfactory life. After all, even children born of an afflicted parent still have a 50 percent chance of escaping the disease. And even if afflicted themselves, such people will probably enjoy some thirty years of healthy life before symptoms appear. It is also possible, although not at all likely, that some might not mind the symptoms caused by the disease. Optimists can point to diseased persons who have lived fruitful lives, as well as those who seem genuinely glad to be alive. One is Rick Donohue, a sufferer from the Joseph family disease: “You know, if my mom hadn’t had me, I wouldn’t be here for the life I have had. So there is a good possibility I will have children.”¹³ Optimists therefore conclude that it would be a shame if these persons had not lived.

Pessimists concede some of these facts but take a less sanguine view of them. They think a 50 percent risk of serious disease such as Huntington’s is appallingly high. They suspect that many children born into afflicted families are liable to spend their youth in dreadful anticipation and fear of the disease. They expect that the disease, if it appears, will be perceived as a tragic and painful end to a blighted life. They point out that Rick Donohue is still young and has not experienced the full horror of his sickness. It is also well‐known that some young persons have such a dilated sense of time that they can hardly envision themselves at 30 or 40, so the prospect of pain at that age is unreal to them.¹⁴

More empirical research on the psychology and life history of suffers and potential sufferers is clearly needed to decide whether optimists or pessimists have a more accurate picture of the experiences of individuals at risk. But given that some will surely realize pessimists’ worst fears, it seems unfair to conclude that the pleasures of those who deal best with the situation simply cancel out the suffering of those others when that suffering could be avoided altogether.

I think that these points indicate that the morality of procreation in such situations demands further investigation. I propose to do this by looking first at the position of the possible child, then at that of the potential parent.