The figures were disclosed by Professor Lord Winston, the test tube baby pioneer, whose clinic at Hammersmith hospital, London, is one of four in the country permitted to carry out the work by the Human Fertilisation and Embryology Authority.
The authority is preparing a consultation paper on the technique, called pre-implantation diagnosis, in which embryos are selected to be free of genetic defects before being replaced in the womb, following concerns expressed by pro-life groups that scientists are "meddling in human evolution". A spokesman for the authority said yesterday: "This is one of the biggest issues we are dealing with. The implications are enormous."
Lord Winston said the technique of pre-implantation diagnosis was the last hope for desperate parents who had suffered repeated miscarriages or seen previous children die. The technique has so far been used in a handful of fatal disorders caused by single genes including cystic fibrosis, Duchennes muscular dystrophy and Taysach's disease. A test for the breast cancer gene, BrCaI, that gives women who inherit it an 80-90 per cent chance of developing the disease, was likely to be the next development, he said.
However, he dismissed suggestions that advances in the technique would usher in a new era of designer babies and trigger demand from parents for socially desirable characteristics in their children.
Speaking at a meeting organised by the Centre for Bioethics and Public Policy, which has warned that pre-implantation diagnosis could be the start of a slippery slope towards eugenics and the quality control of children, he said: "I have no doubt that its uses will be extended but in a limited way. In spite of the exaggerated claims made for it, pre- implantation diagnosis seems to me a relatively insignificant technology. It is of limited value for a small number of parents but those parents are desparately deserving of something better than the alternatives."
Parents carrying a gene for one of the rare disorders currently faced an appalling choice between abortion, taking a "russian roulette" style chance on having an affected baby or remaining childless.
Dr David King, editor of Genethics News, predicted that developments in the technology over the next decade would extend the availability of genetic testing and make it possible without the invasive procedures involved in extracting eggs and replacing embryos. Even though most human characteristics were controlled by multiple genes, sophisticated techniques of embryo selection could increase the chances of having a healthy baby.
"We will begin to hear that sex is for fun but having children is a serious matter which must not be left to chance. We will be told that children have a right to the best genetic chance in life," he said.