American Scientist

Redesigning Humans: Our Inevitable Genetic Future. Gregory Stock. x + 277 pp. Houghton Mifflin Company, 2002. $24.

In his 1923 paper "Daedalus; or, Science and the Future" (which appeared in book form the following year), the British socialist and geneticist J. B. S. Haldane imagined a world in which humans controlled their own evolution. There, through directed mutation and use of in vitro fertilization ("ectogenesis"), the human race had been physically and mentally transformed. Haldane dismissed potential objections to this project based on traditional morality; in his view, our ethics would and should ultimately adapt to our science. He noted that every new invention, especially in biology, initially strikes us as repugnant:

The chemical or physical inventor is always a Prometheus. There is no great invention, from fire to flying, which has not been hailed as an insult to some god. But if every physical and chemical invention is a blasphemy, every biological invention is a perversion. There is hardly one which, on first being brought to the notice of an observer from any nation which had not previously heard of their existence, would not appear to him as indecent and unnatural.

However, he observes, these same inventions come in time to be taken for granted. (In direct response, British mathematician and philosopher Bertrand Russell published Icarus, or the Future of Science, which argues that such power would ultimately be used not for idealistic ends but to strengthen the power of dominant groups.)

Although Gregory Stock's Redesigning Humans was written with less flair and from a very different political perspective, it contains many echoes of Daedalus: the Promethean imagery, the admiration for "early adopters," the prediction that motherhood will be replaced by reproduction in a laboratory, and especially the contemptuous rejection of ethical objections to the project of remaking humanity. Stock has little patience with those who are troubled by questions of morality, or even of risk. In his view, we "should deal with actual rather than imagined problems." We cannot know what future problems will be, he argues, and a focus on "nebulous future possibilities" only hinders progress. He further posits that it is misleading to think, as skeptics do, that there is a trade-off between meager benefits and great dangers, because the risks are actually minor and controllable, whereas the potential benefits are huge.

According to Stock, the benefits will derive from use of "germinal choice technology," especially the ability to pull desired genes from elsewhere through the use of artificial chromosomes. (Although he is not cited, the geneticist H. J. Muller coined the term "germinal choice" in the 1960s to describe a plan to promote the artificial insemination of women with the sperm of extraordinary men.) Stock asserts that germinal choice technology will allow us to markedly enhance the physical, mental and temperamental traits of our children. He disposes of the difficult scientific issues involved even more casually than the moral ones.

Stock acknowledges that the project rests on assumptions about the causal significance of genes for the traits of interest, assumptions that he claims are legitimated by twin and family studies demonstrating that genes are the most important factors in determining "the defining aspects of personality and temperament." But the argument is vitiated by a number of confusions. First, Stock equates "genetic" with "biological," assuming, for example, that any tendency present from birth is genetic—notwithstanding his own interesting discussion of research demonstrating that genetically identical mice raised as far as possible in the same environment show significant variability in life spans. Moreover, the studies on which he relies can only establish estimates of heritability, not the importance of genes in determining phenotypes. One reason is that such estimates depend on the particular mix of both genotypes and environments. Thus the heritability for any variable trait in a population of clones is zero—not because genes are irrelevant to the expression of the trait, but because there is no genetic variability. By the same token, when a mixed outbreeding population develops in a controlled, uniform environment, nearly all the variation must be genetic in origin and the heritability of any variable trait therefore close to 1.0. Another reason is that, as Stock himself notes, the same genotype may be expressed differently in different environments. That is why plant and animal breeders take as many different genotypes as possible and allow them to develop in as many different environmental dimensions as they think possibly relevant.

When it comes to human beings, where such experiments are impossible, it is necessary to make judgments about the nature of the environments to which people will be exposed. The significance of heritability estimates therefore depends on essentially political suppositions about the fixity of existing social arrangements. Stock acknowledges as much when he notes that heritability is only valid "for the range of environments where the studies took place," but he then removes the sting by asserting that the environments are not likely to change. Ironically, Stock is as conservative in his social assumptions as he is speculative and swashbuckling about the science.

Perhaps his most provocative claim is that the advance of germinal choice technology is inevitable. One reason is that it represents spinoffs of basic research that no one wants to halt. Another is that it fits with parents' strong motivations to give their children the best possible chances in life. A third is that, irrespective of their values, both individuals and nations will be forced by competitive pressures to participate. (Stock apparently does not see the irony of this claim in a book that extols "free individual choice.") According to his logic, attempts to bar the technology will fail (and if we try to exert more than a very modest degree of oversight, the enterprise will be driven underground, increasing the likelihood of abuse). Regulation can determine where germinal technologies develop and how publicly they are used, but in the end, he asserts, resistance is futile, since it is impossible to stop the technology everywhere. If the Chinese embrace it while we hold back, eventually we will only have to scramble to catch up. Fortunately, evolution guarantees that our values will ratify the science: Our descendants "will be committed to the process of human enhancement and self-directed evolution. This we know, because without this commitment they would lag behind and be displaced by those who are more aggressive in this regard."

To those who worry that germinal choice technology will be accessible only to the well-off and will thus increase inequality, Stock replies that we should try to make the technology so cheap that all can afford it. In a particularly audacious move, the fairness argument is stood on its head. Making the technology commonplace becomes "a step towards equalizing life's possibilities," since the mass of people have much to gain from genetic interventions. The "well-endowed elite," on the other hand, has much to lose—and so will self-servingly warn of "eugenics" and other ostensible dangers. But Stock does not consider the possibility that if universal access were achieved, the point of the enterprise would be undermined. Although a longer life span or better memory could in principle benefit everyone, other advantages are only comparative; they provide an edge in a competition with others. If everyone ends up taller, there will be no overall benefit to compensate for the financial expense and the risks and side effects of treatment.

Redesigning Humans is essentially a lawyer's brief for the benefits of germinal choice technology and the costs of regulation. Stock is right that there are many foolish arguments against altering our genetic makeup. He takes effective aim at those who sacralize the genome, or claim a "right" to an unaltered genome, or base opposition to particular practices on intuitive feelings of repugnance or on undefended claims about what it means to be human. But these are relatively easy targets; the more challenging issues are glossed over or ignored.

Stock and other enthusiasts for human genetic engineering, such as the philosopher Gregory Pence and the biologist Lee Silver, assume that the market simply responds to consumer demands. Even if that were true in Adam Smith's day, our economy is dominated by corporations that shape as well as respond to preferences. Whereas Stock takes our needs and desires as given, critics fear their manufacture by biotechnology companies seeking new customers. These critics would contest Stock's assumptions both about what people want and why they want it, as well as the point of an arms race that has the potential to leave everyone worse off than they were before.

For a book that is generally welcoming to the new genetic technologies but takes the problems seriously, readers should tackle From Chance to Choice by Allen Buchanan and others (reviewed in the January–February 2001 issue). Although not as easy a read as Redesigning Humans, it is ultimately much more rewarding.

The current public debate about genetic interventions, which features Gregory Stock squaring off against Francis Fukuyama, is sadly impoverished. [Editor's note: Fukuyama's new book, Our Posthuman Future, is reviewed by Dan Brock in this issue.] For the sake of thoughtful public policy, we need to do better.