On the Necessity of Practising a Benign, or Utopian, Genetics

John Dupré

  • The Lives to Come: The Genetic Revolution and Human Possibilities by Philip Kitcher
    Allen Lane, 381 pp, £20.00, April 1996, ISBN 0 7139 9129 1

Scientists would sometimes like us to believe that science is just too difficult for the comprehension of ordinary mortals. Given the increasing diversity of specialities, moreover, there is no chance for anyone, scientist or otherwise, to understand more than fragments of it. Only committees of complementary experts, it would appear, will be able to make intelligent decisions when scientific advances raise questions of science’s answerability to society. This fear is greatly exaggerated. Although there are areas of science which it requires familiarity with advanced mathematics to understand, these are few and, as a rule, have no great relevance to public policy. Despite its prestige, high-energy physics has little obvious practical relevance to anything but the level of public funding of high-energy physics. A good sense of the fundamentals of most science is not beyond the reach of the educated outsider. The level of expertise required to grasp the broad implications of research is not the same as that required to advance that research. The real problems lie elsewhere.

If a tolerable level of scientific understanding is not beyond the reach of the general public, who might be expected to provide it? Most of us have neither the time nor the inclination to return to the classroom for a refresher course in molecular biology or microeconomics. If the goal were simply to provide access to the technical details there would be no problem: this would best be provided by the scientists themselves. But it is not the only or even the main goal. What we really need is an exposition of the science together with an evaluation, first, of its epistemic merits and, second, of its implications for society generally. With the former, scientists are likely to be advocates rather than disinterested observers, and the latter are not matters about which scientists have any particular expertise.

The philosophy of science might seem particularly well equipped to meet this need. Unfortunately, however, philosophers of science show little appetite for such work, concerning themselves rather with esoteric matters in the theories of confirmation, explanation, causation and so on. And where they do aim to advance understanding, they often seem more concerned to obtain the respect and approval of scientific practitioners than with presenting an external, perhaps critical, perspective. Nevertheless, in The Lives to Come, Philip Kitcher provides an outstanding illustration of what the philosophy of science can contribute to public understanding.

Molecular genetics, the topic of Kitcher’s book, is surely the area of contemporary research with the greatest potential relevance to society. In an astonishingly short-time, scientists have learned to read the billions-long sequences of molecules that comprise DNA, have described in great detail its basic functioning, and have discerned connections between defects in the DNA and disease. Radical transformations of the practices of medicine and law enforcement, and a revival of eugenics, are among the benefits (or fears) widely advertised by enthusiasts for this project.

Kitcher is both sensitive to the potentially adverse consequences of molecular genetics, and enthusiastic about the potential benefits. On occasion, however, this enthusiasm may have more to do with the pure excitement of the science than with any very clear practical consequences in the foreseeable future. The most commonly heard justification of the billions currently being spent on the Human Genome Project is that it will lead to advances in medicine. Yet this proves to be the area of greatest disappointment when we confront the reality. The example to which Kitcher, in common with other enthusiasts, constantly recurs is that of phenylketonuria, or PKU. Children born with PKU lack a gene necessary for the metabolism of a common amino-acid, phenylalanine. Under normal circumstances they suffer severe mental retardation. By providing them with special diets very low in phenylalanine, it has proved possible for many such children to develop nearly normally.

Kitcher describes the test for PKU as a ‘wonderful success story’. But is it? First, as Kitcher also describes, the history of PKU treatment includes many mishaps, including children being misdiagnosed with the condition and suffering severe damage from the special diet. Even apart from such mistakes, the diet is both expensive and unpleasant. The treatment is hardly a medical triumph on the level of smallpox vaccine or penicillin, and the number of beneficiaries is small. Moreover, the success, such as it is, has very little to do with genetic medicine. While it is true that the genetic basis of the disease is now fairly thoroughly understood, the treatment was developed long before this was the case. All that modern genetics has contributed is a more reliable test for those children with access to state-of-the-art medical care. As Kitcher makes clear, finally, PKU is a thoroughly atypical case. More typical is Huntington’s disease, which produces catastrophic neural deterioration in middle age. Though its genetic basis is now confidently identified, this has produced no progress towards an effective therapy.

In discussing the mapping of the human genome Kitcher remarks that ‘good maps’ have enabled researchers ‘to journey to understanding’ and cites Huntington’s disease as a ‘prominent example of a success story’. But impressive though the science here may be, the absence of any insight into a possible therapy is indicative of the dearth of understanding. It seems very possible, moreover, that the complexities of the development of genetic flaw into illness are so great as to make the identification largely irrelevant to the search for intervention. Here there are potentially deep grounds for scepticism about the benefits of genetic technology. The successes of genetics, from Crick and Watson to the astonishing contemporary technologies for harnessing the genetic machinery of micro-organisms, make it difficult not to have an exaggerated view of the importance of genes to life. This has been exacerbated by Richard Dawkins’s eloquent and widely-read attempts to persuade us that we are nothing more than a gene’s way of making another gene. But the truth is that neither the chicken nor the egg comes first. Bodies, artefacts such as nests and burrows, proteins and genes all replicate themselves, and all require a vast and diverse array of collaborators to achieve this replication. There is nothing so causally special about genes that we should suppose they provide the most basic insight into disease or the most promising site for intervention.

A very different possible benefit lies in the fight against crime. Violent criminals often leave parts of their substance at the scene of the crime, and blood or semen can now betray their sources. Kitcher explains that a DNA profile is not quite like a fingerprint, and various fallacies must be guarded against in interpreting such evidence. Given the notorious difficulty most people have in thinking clearly about probabilities, some of the complexities should cause concern in the context of a system of jury trial. Nonetheless, with proper precautions, it is possible to provide a unique description of a person’s DNA. Kitcher envisages a future in which everyone’s DNA profile would be on record with the police, so that whenever criminals did leave bodily material at the crime scene – semen in rape victims, skin under the fingernails of murder victims – the police would immediately know whom to arrest. One may doubt whether the benefits of such a scheme would in the long term be worth the price, however. As Kitcher observes, criminals will adapt. He even reports rumours that there is already a market among New York prostitutes for used condoms. A different worry concerns the general desirability of convicting criminals on the basis of procedures that neither the criminal nor the layman is likely to understand. Clearly there is a possibility for abuse here: the very kind of abuse which the jury system, likely to be made effectively obsolete by such methods of criminal investigation, was designed to avoid.

The most clearly established consequence of genetic technology, however, is the ability not to cure but to predict disease. The possibilities of prenatal detection of gross chromosomal abnormalities, such as Down’s syndrome, are now familiar, and the number of more subtle but deadly genetic diseases that can at least in principle be detected grows rapidly. It is also quite likely that predispositions towards such widely prevalent killers as heart disease and cancer will be detectable (a claim already established, apparently, for some cancers). I am less confident than Kitcher that these discoveries will have much effect on the development of useful therapies. But the consequences of the predictions themselves are potentially profound.

Health insurance provides a striking example. Insurance is a scheme for spreading risk, and the more possible it becomes to predict disease the less the concept of risk applies. Increasingly, insurance companies will not wish to insure those at high risk against expensive diseases, and those with genetic good fortune will not want to spend much on insurance. We may therefore hope that genetic medicine will finally force the realisation, even in the United States, that health care policy requires a social decision on the allocation of costs rather than individual decisions on the hedging of risks.

The more general consequence of increased prediction, and the largest single focus of The Lives to Come, is the invitation to eugenics. As Kitcher is well aware, eugenics has an almost wholly unsavoury connotation. Nevertheless, he insists that contemporary genetic knowledge forces us to confront the issue and recognise the possibility, even the moral necessity, of practising a benign or, as he describes it, ‘utopian’ eugenics. In fact, eugenics is already with us. In affluent circles at least, amniocentesis and abortion of genetically abnormal foetuses is routine, and The Lives to Come opens with harrowing descriptions of the plight of children dying of incurable genetic diseases. Much more problematically, selective abortion of female foetuses in Northern India is already producing a substantially skewed sex ratio. Even assuming we have no serious doubts about allowing a pregnancy to be terminated when it is known that the child would be condemned to a brief and pain-filled life which would cause suffering to all involved, the line between this and the case of sex selection is still extremely difficult to draw. If, as we are constantly being told in the media, there are genes for criminality, homosexuality, high or low intelligence, obesity and so on, and such genes may soon be prenatally detectable, what grounds, if any, should we find acceptable for decisions to terminate a pregnancy?

Kitcher’s answer is that we cannot avoid making judgments about the probable quality of life, and have a right, perhaps even a duty, to terminate a pregnancy when the quality of life predicted is sufficiently low. Kitcher defines quality of life in terms of the ability to determine what is truly important to a person, the extent to which life-goals are realised, and the balance of pleasure and pain. Although I applaud his willingness to provide specific criteria for these difficult decisions, I am doubtful of their adequacy. Kitcher’s views reflect an uncompromisingly romantic work ethic: goals and their achievement are what give people real worth. ‘The young hero gazes into the dim distance, squares his shoulders, and ventures forth to realise his ambitions.’ Comparing a young man ‘dedicated to tracking down the causes of a deadly disease’ with another ‘with no clear project, no obvious opportunities’, Kitcher suggests that ‘we would not find the second man’s early death so tragic as that of the first, the man with “all the world before him”.’ Of course he doesn’t suggest that we should look for drifter genes and abort foetuses which give indications of a difficult or troubled life ahead. But the specificity of his own criteria prompts serious worries about the applicability of any criteria at all for such a judgment.

Consider again the selective abortion of female foetuses, something most Westerners find highly distasteful. Kitcher remarks that Nazi doctors and Northern Indian peasants have one thing in common, that they hope ‘to modify the frequency with which various characteristics are present in future populations’. But the peasants have no such hope, and very probably have given no thought to such frequencies. As he notes later, it is implausible to think of these peasants as moral monsters. Rather, they are struggling with dire economic conditions and the particular cultural exigencies of the caste system, and these circumstances make the birth of a girl a severe misfortune. Kitcher, as a liberal American academic, is unsurprisingly confident that selective abortion of foetuses with a predisposition to homosexuality would be morally intolerable. But suppose there were religious communities in which the prospect of giving birth to a child so severely mentally handicapped as to be incapable of forming a conception of the good life would be considered a minor misfortune compared to that of giving birth to a child who turns out to be homosexual. Consideration of the diversity of cultural contexts into which the technology is likely to be imported should make us worry about the likely relevance of any specific conception of the value or quality of human life.

The last example raises a more general worry. Public perception of the scientific debate over whether there are ‘genes for homosexuality’ often assumes that what is at stake is the idea that there is a gene or set of genes possessed by all, and only, homosexuals. But in the technical language of geneticists, as Kitcher reminds us, it means nothing of the kind. Something is a gene ‘for’ homosexuality if it is a variant (or allele) such that a person with this allele is more likely to be homosexual than someone with a different allele at this locus. (And even this is said to hold relative only to some specified external and genetic background.) This is a subtle concept, and Kitcher nicely illustrates the dangers of misunderstanding it poses by reference to the history of the once infamous XYY chromosome. It was once noticed that men in penal and mental institutions had a higher incidence of this abnormality than did the general population, and the idea of it as a genetic basis for criminality received a great deal of public exposure. It is entirely likely that women decided to terminate pregnancies on learning that their foetus had this abnormality, and technically speaking it may even be correct to refer to the XYY genotype as ‘for’ criminality. However, it is also the case – never, as far as I know, widely publicised – that 96 per cent of men with the XYY genotype lead perfectly ordinary crime-free lives. Once again, the general point is that genes are only one contributor to the almost unimaginably complex set of processes by which a fully fledged human is produced; and apart from gross and catastrophic defects, the effect of a particular genetic variant is likely to depend on other genetic and environmental factors in indefinitely complex ways. If there are genes ‘for’ violence, homosexuality, intelligence etc, they will almost surely be of this mildly predisposing variety. Fortunately, perhaps, this makes the relevant eugenic projects not only even more morally problematic, but also in practice almost certainly infeasible. One crucial moral is that if we are to have the kind of public understanding essential for intelligent discussion of these issues, scientists must learn to be much more careful than they often are in qualifying and explaining their easily sensationalised claims.

Finally, Kitcher raises another important issue about access. Genetic testing is expensive, and as more information is gathered, more expensive testing will become possible. There is an obvious concern that it will become increasingly a medical technology for the well-off, and genetic disease just another burden for the poor. Kitcher is clear that general access to testing is a condition for its introduction as medical practice.

However, one cannot help doubting whether this is likely to happen. Moreover, given its expense, and that universal access would presumably mean that this expense would fall on government, one may wonder whether genetic testing could possibly be a cost-effective use of scarce resources. In the United States there is still no access across the population to routine prenatal care or childhood immunisations; and in poorer parts of the world millions of children die every year of diarrhoea. Universal access to sophisticated genetic testing hardly seems a realistic expectation. Although Kitcher argues strongly for the necessity of state provision of a basic level of essential health care, he also expresses sympathy for a two-tier system under which more elaborate medical treatment could be privately provided. It is likely that much genetic testing will find itself in this upper, exclusive tier, and contribute to social inequality.

Kitcher is highly optimistic about the likely benefits of the genetic revolution, and cautiously optimistic about the possibility of avoiding the dangers. I am less convinced of the likely benefits, and less sure that the dangers can be circumvented. But Kitcher’s is in no sense a one-sided presentation of the issues: all, or almost all, of the difficulties I have mentioned here are discussed in detail. And I have no doubt that he is right that a reappraisal of the permissible limits of eugenics has become unavoidable.