Advances in biotechnology are so rapid that within a decade reproductive scientists will be able to engineer the human germline not just to free fetuses from inherited disease, but to influence various aspects of normal fetuses so that the resulting individual will be genetically enhanced. This is not science fiction but science fact; it is almost upon us. And despite the great anxieties expressed in some quarters about what this means for humankind, people everywhere are already voting with their wallets to take advantage of anything that biotechnology offers in the way of curing diseases, lengthening lifespan, restoring youthful vigour, and giving their children a head start.

In the two books here under review, sharply opposed views are taken about the acceptability of these developments. Francis Fukuyama is against them, Gregory Stock is for them. And it has to be said at once that nothing could be better calculated to promote the future of biotechnology than the remarkable asymmetry between their two accounts. Fukuyama’s essentially conservative case is no match for the well-informed and sensible considerations put forward by Stock. The two books should be bound together and distributed to every household by the public authorities, for on this vitally important matter it is essential to see for themselves how social scientists (like Fukuyama) who question the promise of biotechnological progress measure up against natural scientists (like Stock) who know what they are talking about in this domain and are able to put that promise into perspective.

That is not to say that Fukuyama fails to marshal the best that can be said for the opposition to biotechnological advance, which he presents in the form of a heterogeneous collection of arguments aiming to show, for example, that parents might make genetic choices for their offspring on the basis of current fashions that are later embarrassing or disadvantageous for them, that greatly increased longevity might have unacceptable social and financial costs, that, as human-induced damage to ecosystems shows, deference to nature is safer and better than interference with it – and so on. His chief argument is that genetic engineering threatens the loss of our human nature, and that our ethics, politics and law must be mobilised to protect the right of future people to remain human.

In essence Fukuyama’s argument is that there is an intimate connection between human nature and notions of rights, justice and morality, and he holds this despite the fact that most philosophers and jurisprudents deny that there is such a thing as a human essence which settles what is humanly right and wrong. In reasserting the older view that there is such a thing as human nature, and that understanding it justifies our attribution of rights, Fukuyama aims to show that future human beings have a right to be human in exactly the way humans are human now.

Even apart from their doubtful essentialist premises, Fukuyama’s arguments fail at several crucial points. One is that if we humans engineer a different human future, this will be an entirely natural thing for us to do, because the intelligence we have by nature has always led us to modify ourselves and the world around us, in search of advantages in any and all ways we were capable of doing it. The cereals we eat, our dogs and horses, the very landscape, are the results of our natural activity of investigating, understanding and then changing things. Living in centrally heated houses, speaking to each other on the telephone, surfing the Internet, taking antibiotics, starting pregnancies by in vitro techniques and concluding them by Caesarean section – in all these activities what is natural to us has been extended and enriched by our natural endowment of intelligence. If one were to attempt an essentialist argument, it would not be with Fukuyama’s backward-looking aim of trying to keep us as we are for ever, but instead to say: it is essential to us to grow and change, not just as individuals, but also as a species. Only think how things might have turned out if Neanderthals had had a say in whether the future would belong entirely to Cro-Magnon Man.

Stock is not a mere visionary, starry-eyed about a future of supermen and superwomen living disease-free, super intelligent and beautiful lives. He makes the excellent point that biotechnology is here to stay, and one way or another it will be used, once germline engineering and other techniques are safe and available. The point is not to try, Canute-like, to turn back the tide, but to understand the possible developments – which, incidentally, are neither as swingeing nor as terrifying as the scaremongers make out – and to put them into perspective. How the future of biotechnology will be used can already, to a large extent, be inferred from the kinds of things people already do (combating ageing, preventing genetic defects in offspring). These are endeavours to improve and ameliorate the human condition. Stock quotes DNA discoverer James Watson: ‘If we could make better human beings by knowing how to add genes, why shouldn’t we?’

Both Fukuyama and Stock recognise that the opposition to biotechnology comes from two main sources – religious beliefs to the effect that we must not interfere with what God has created and the deep sensitivities about eugenics that have developed as a consequence of the use made of it by the Nazis. The first consideration can be rapidly dismissed: ancient superstitions have always stood in the way of human progress of all kinds, and cannot be taken seriously. The eugenics issue is more serious, and here the question is whether anyone is contemplating the forced or mandatory use of biotechnology to make future people conform to some dictator’s stereotype. The answer is an emphatic No. Almost all of what will happen in the future of biotechnology will be driven by individual choices.

Stock responds to Fukuyama by challenging the idea that the anti-progressive case can be successfully based on the idea of a ‘human right to an unaltered genetic constitution’. The fact is, the preferences of parents and grandparents, none of whom consult their descendants because they cannot do so, already determine their descendants’ genetic constitution, and do so far more randomly and accidentally than if parents were choosing the genetic endowment of their offspring in a laboratory. The genetic dance of transmission and variation will continue, but in a more deliberate way, and almost always in the direction of what we already value and admire in human nature.

Critics say that society will fragment, the rich buying genetic advantages for their offspring; that we will ‘lose our spiritual moorings’; that ‘relationships and values will be distorted’. The rich already buy many advantages: there will be nothing new there. The other two objections are unmeaning; people will find their way and forge relationships and values as they always have, no matter how tall, good-looking or smart they become. As for the two practical objections (genetic time-bombs, and the impoverishment of the gene pool), Stock shows, in an absorbing account of how the relevant biotechnologies work, that neither is true.

Overall, Stock makes a convincing case for the view that, as a product of human intelligence and its creative impetus to improve the human lot, biotechnology is a major force for future good, and should be welcomed in a sane, sensible, and practical spirit, so that it can be well regulated and well used for the best ends.