People with inherited forms of cancer have won the right to select embryos free from genes that might trigger the disease in future generations, The Times has learnt.

Four couples affected by a genetic form of bowel cancer will start the procedure by the end of the year, after the Government’s fertility watchdog allowed a London clinic to screen IVF embryos for the disorder.

One of the patients, a 35-year-old accountant from Bristol, said: “We are overjoyed to have been given this chance, not only to do as much as possible to make sure our children don’t have this gene, but to stop them from passing it on.”

The ruling by the Human Fertilisation and Embryology Authority deepens the controversy over designer babies. It sets a precedent that will allow doctors to “cherry-pick” embryos for a much wider range of traits than at present. Applications to extend the procedure are expected within months.

Such tests can potentially eradicate some disorders, enabling parents to be certain of having healthy children. But critics said that the decision will push Britain farther towards “designer babies” chosen for social reasons.

Paul Serhal, of University College Hospital, will be allowed to screen embryos for the gene that causes familial adenomatous polyposis (FAP) - an aggressive colon cancer.Only embryos free of the faulty gene will be implanted. Infants would otherwise have a 50 per cent chance of inheriting it.

The test was previously approved only for childhood or untreatable disorders such as cystic fibrosis and Huntington’s disease.

FAP does not generally develop until between 20 and 40 and the risk can be reduced by surgery. Opponents argue that the test will deny life to embryos that would not fall ill for decades, and might not develop cancer. Using it to screen for breast cancer is more controversial still. Some genes raise the risk to 80 per cent but do not always cause the disease.

Mr Serhal, whose licence application was revealed by The Times in June, said: “This will be able to wipe out a defective gene completely, allowing couples to have children without the fear that they may be passing on a terrible illness.”

But many people with genetic diseases may not opt for the test. Emma Stevenson, from Bolton, who carries a bowel cancer gene, said that she would not have chosen it when she conceived her daughter, Katie. “I have the gene and I’m glad to know, but I don’t think I would have wanted Katie tested,” she said.