The Language of the Genes. Steve Jones

endowment’ – it said – ‘is a hundred times more important than the dispute over capitalism or socialism.’

      His thoughts were echoed in Mein Kampf: ‘Whoever is not bodily and spiritually healthy and worthy shall not have the right to pass on his suffering in the body of his children’. Hitler took this to its dreadful conclusion with the murder of those he saw as less favoured in order to breed from the best. The task was taken seriously, with four hundred thousand sterilisations of those deemed unworthy to pass on their genes, sometimes by the secret use of X-rays as the victims filled in forms. Those in charge of the programme in Hamburg estimated that one fifth of its people deserved to be treated in this way.

      By 1936 the German Society for Race Hygiene had more than sixty branches and doctorates in racial science were offered at several German universities. Certain peoples were, they claimed, inferior because of inheritance. Half of those at the Wannsee Conference (which decided on the final solution of the Jewish problem) had doctorates and many justified their crimes on scientific grounds. The eugenics movement in Germany was opposed to abortion (except of the unfit) and imposed stiff penalties – up to ten years in prison – on any doctor rash enough to carry it out. The number of children born to women of approved stock went up by a fifth. The Hitlerian conjunction of extreme right wing views, an obsession with racial purity and a hatred of abortion has its echoes today.

      Concern for the purity of German blood reached absurd lengths. One unfortunate member of the National Socialist Party received a transfusion from a Jew after he had been in a road accident. He was brought before a disciplinary court to see if he should he excluded from the Party. Fortunately, the donor had fought in the First World War, so that his Jewish red cells were – just about – acceptable.

      The disaster of the Nazi experiment ended the eugenics movement, at least in its primitive form. Its blemished past means that human genetics is marked by the fingerprints of its own history. It sometimes seems to find them hard to wipe off. They should not be forgotten now that the subject is, for the first time, in a position to control the biological future.

      Galton and his followers felt free to invent a science which accorded with their own prejudices. They believed that the duty to genes outweighs that to those who bear them. They were filled with extraordinary self-assurance and great weight was placed on their views although in retrospect it is obvious that they knew almost nothing.

      Today’s new knowledge is as controversial as was the old ignorance. Even so, disputes among modern biologists are not about the vague general issues that obsessed their predecessors. Instead they concern themselves with the fate of individuals rather than of all humanity. Genetics has become a science and, as such, has narrowed its horizons.

      Nevertheless, it raises ethical issues which will not go away. The newspapers are filled with debates about the morals of gene therapy or of human cloning, neither of which show any sign of becoming a reality. However, the diagnosis of defective genes before birth has already shifted the balance between birth and abortion to reduce the number of damaged children. This raises passions, from those who feel – in spite of the high natural wastage of fertilised eggs – that all foetuses are sacred, to others who consider that to pass on a faulty gene is equivalent to child abuse. Genetics presents a more universal difficulty – the problem of knowledge. Soon, it will tell many of us how and when we may die. Already, it is possible to diagnose at birth genes which will kill in childhood, youth or middle age. More will soon be found. Will people want to know that they are at risk of a disease which cannot be treated? Many genes show their effects in those who inherit damaged DNA from each parent. As everyone is likely to pass on a single copy of at least one such gene, will this help to choose a partner or to decide whether to have children?

      Attitudes to inborn disease are flexible. In Ghana, babies are sometimes born with an extra finger or toe. Some tribal groups take no notice, others rejoice as it means that the new member of the family will become rich; but others, just a few miles away, regard such children with horror and they are drowned at birth. Even Christianity has seen the genetically unfortunate as less than human. Martin Luther himself declared that Siamese twins were monsters without a soul. Attitudes to genetics will always be influenced by those to abortion, which vary with time and place. St Augustine saw a foetus as part of its mother and not worthy of protection and in spite of its present views the Catholic Church did not condemn abortion until the thirteenth century. Ireland has a constitutional clause that establishes the right to life of the unborn child; while across the Irish Sea abortion until the third month is available almost on demand. Embryo research (which is becoming important with the discovery that embryonic cells can be used to treat adult disease) is forbidden in Germany but lightly controlled in Britain. All this shows how hard it is to set ethical limits to the new biology.

      The problem can be illustrated with some old-fashioned biological discrimination. There has always been prejudice against certain genes, those carried on the chromosomes that determine sex. Women have two ‘X’ chromosomes, men a single X chromosome and a much smaller ‘Y’. All eggs have an X but that of sperm are of two kinds, X or Y. At fertilisation, both XY males and XX females are produced in equal number. Sex is as much a product of genes as are blood groups.

      How the value of these genes is judged shows how biological choice can depend on circumstances. Sometimes, Y chromosomes seem to be worth less than Xs. When it comes to wars, murders and executions, males have always been more acceptable victims than females. But the balance can shift. Many parents express a preference for sons, especially as a first-born. Some even try to achieve them. The recipes vary from the heroic to the hopeful. In ancient Greece, to tie off the left testicle was said to do the job, while mediaeval husbands drank wine and lion’s blood before copulating under a full moon. Less drastic methods included sex in a north wind and hanging one’s underpants on the right side of the bed.

      To sell gender is an easy way to make money. It has, after all, a guaranteed fifty per cent success rate. Today’s methods vary from the use of baking soda or vinegar at the appropriate moment (to take advantage of a supposed difference in the resistance of X and Y-bearing sperm to acids and alkalis) to sex at particular times of the female cycle. A diet high or low in salt is also said to help. Such recipes are useless and some of those who sell them have been prosecuted for fraud.

      Now, fraud is out of date. Sex can be chosen in many ways. One is to separate X and Y sperm and to fertilise a woman with the appropriate type. The methods are not absolute, but shift the ratios by about two to one for males and four to one for females. Since Louise Brown in 1978, thousands of children have been born by in-vitro fertilisation, with sperm added to egg in a test-tube. A single cell can be taken from the embryo and its sex determined (and, indeed, as young male embryos grow faster, simply to choose the largest embryo biases the ratio of males). Only those of the desired gender are implanted into the mother. This technique has led to the birth of hundreds of babies.

      Pregnancy termination is a less kind, but equally effective, way of choosing the sex of a child. Aristotle himself felt that a male foetus should be protected from abortion after forty days, but a female only after ninety. A recent survey of geneticists themselves showed that, in Holland, none would accept pregnancy termination just to choose the sex of a child, in Britain one in six, and in Russia nine out of ten. The Indian government was forced to shut down clinics which chose the sex of a baby with a test of the chromosomes of the foetus and aborted those with two Xs. More than two thousand pregnancies a year were ended for this reason in Bombay alone. The main reason was the need for large dowries when daughters were married off. The advertisements said ‘Spend six hundred rupees now, save fifty thousand later.’ The preference is an old one. A nineteenth-century visitor to Benares recorded that ‘Every female infant in the Rajah’s family born of a lawful wife, or Rani, was drowned as soon as it was born in a hole in the earth filled with milk.’ The rulers’ many wives were said to have produced no grown-up daughters for more than a century. The government nowadays pays a bonus for girl babies, but some states now have four females to five males and the country as a whole has a deficit of girls and women equivalent to the entire British female population.

      All these methods interfere with genes. Their acceptability varies from the reasonably uncontentious choice of sperm to a crime where the murder of girl children is concerned. Where to draw the line