Sometimes the link between the Utopian novel and eugenics is painfully clear. Shaw felt that 'if we desire a certain type of civilization we must exterminate people who do not fit into it'. H. G. Wells, in his scientific vision of the world to come, the (now obscure) Anticipations of the Reaction of Progress upon Human Life and Thought, published in 1901, wrote in favour of euthanasia for 'the weak and sensual' and of genocide for 'the dingy white and yellow people who do not come into the needs of efficiency'. Many Utopias would not have been comfortable places for those forced to live in them.
This book has been a tale of how humankind has evolved by the same rules as those that propel less pretentious beings. Humans are, of course, more than apes writ large. We have two unique attributes: to know the past and to plan the future. Both talents guarantee that our prospects depend on much more than genes. Nevertheless, it should be possible to make some guesses from biological history about what the evolutionary forecast might be.
One pessimistic but accurate prediction is that it means extinction. About one person in twenty who has ever lived is alive today, but only about one in a thousand of the different kinds of animal and plant has survived. Our species is in its adolescence, at about a hundred and fifty thousand years old, compared to several times this for our relatives. Its demise is, one hopes (and in spite of the advances of nuclear physics) a long way away and we can at least reflect about what might happen before then.
The rules of evolution are simple and will not change. They involve the appearance of new genes by mutation, their test by natural selection, and random changes as some, by chance, fail to be passed on. To speculate about the future of each process is to predict human evolution. Will the biological Utopia be like its fictional equivalents; will we continue to evolve as rapidly as we have since our beginnings, or is our evolution at an end?
Humans have interfered with their biological heritage since they appeared on earth. Stone tools, agriculture and private property all had an effect on society and in turn on genes. Many people are concerned that the next phase of history will be one in which genetics makes plans for the future. That asks too much of science. Inadvertent change-evolution by mistake-will be far more important than is any conscious attempt to engineer our own biology.
Even the most determined efforts of doctors, genetic counsellors or gene therapists will have only a small effect on the future. Part of that lies in the healing power of lust: in the desire of people to have children for reasons that have nothing to do with science. More is a matter of arithmetic. For recessive conditions, far more genes are hidden in normal people than in those with disease — a hundred times as many for cystic fibrosis, thousands of times for rarer diseases. Whatever happens to those who receive two copies — death in infancy or by pregnancy termination, orcure by gene therapy — is more or less irrelevant to the future. Social pressure against the genetically unfortunate has decreased. In the 1950s a small minority of achondro-plastic dwarves found a spouse, but now more than eighty per cent are married, often to someone else in the same circumstances. They often have children but, even so, the great majority of newborns with the condition appear — as they always have — because of new mutation.
Many inherited diseases appear anew each generation for the same reason. Is, as many dystopians claim, the evolutionary future in danger because of an increase in the mutation rate? H J Muller, who won the Nobel Prize for his discovery that radiation causes mutations, himself wrote a dark novel of the future, Out of the Night, in which life has been blighted by the accumulation of genetic damage. Perhaps modern civilization — with its dubious benefits of nuclear radiation and poisonous chemicals — will damage our genetic heritage. Certainly, such things do alter DNA, but the obvious threats such as man-made radiation and industrial by-products, have a smaller effect than do natural sources such as the radon gas that leaks from granite and the poisonous chemicals found in mouldy food. The Sellafield nuclear power station in the North of England is one of the dirtiest in the western world (and the North Sea its most radioactive body of water). The name of the station has itself mutated from Calder Hall to Windscale to Sellafield in a feeble attempt to calm public suspicion. Compared to other sources of radiation, its effects arc minor. Avid consumers of shellfish collected near the discharge pipe (and there are not many of those) receive about as much excess radiation as those who fly from London to Los Angeles and back four times a year and are exposed to cosmic radiation as a result.
A more subtle transformation has had a dramatic effect on the mutation rate. In the western world at least, a change in the age at which people have children means chat amounts of DNA damage will drop. The rate of mutation goes up with age and the effect accelerates as the years go on. Most mutations (apart from chromosome mutations, most of which are so damaging that they do not pass to the next generation) take place among males. Fathers of thirty-five do not have a rate much greater than those of eighteen, but after that mid-life moment the incidence of damage shoots up (to a rate twenty times higher in pensioners compared to schoolboys). The more old fathers, the more the genetic damage.
People now live for far longer than in earlier times, allowing mutation to take its toll on a higher proportion of the population. The cancer epidemic in the modern world is confined to older people. Cells that give rise to sperm or egg are also exposed to the destructive effects of age, which is why older parents are more likely to have damaged children. Any change in the age of reproduction will hence have an effect on the mutation rate. If the number of elderly parents goes up, there will be more inherited changes; if it decreases, fewer. Social progress has led to just such a shift. The general picture — which applies to much of the third world as well as to developed countries — is subtle and unexpected.
Before the recent improvements in public health most children died young. Parents started having children when they were themselves youthful and continued until death or the menopause. Throughout history the average number of children per couple has been two, or a little more; as, on the average, it still approximately is. The figure is now reached in a new way: not with perhaps a dozen births accompanied by ten deaths in infancy, but with around two planned and healthy offspring.
A drop in infant mortality means less pressure to have children as an insurance against old age. Contraception allows parents to delay their first child (in Britain now until the late twenties, on average) but then to complete their families quickly. Most people stop soon after they have started. As a result, and although the age at which parents have their first offspring has increased, the number of elderly mothers and fathers has gone down. As recently as the 1920s the average Englishwoman began her final pregnancy at over forty; a figure that has dropped by almost ten years. The occasional births to much older women with the help of technology (and the oldest is in her mid sixties) are so rare as to be insignificant.