Two couples whose families have been ravaged by breast cancer are to become the first to screen embryos to prevent them having children at risk of the disease, The Times has learnt.

Tests will allow the couples to take the unprecedented step of selecting embryos free from a gene that carries a heightened risk of the cancer but does not always cause it. The move will reignite controversy over the ethics of embryo screening.

An application to test for the BRCA1 gene was submitted yesterday by Paul Serhal, of University College Hospital, London. It is expected to be approved within months as the Human Fertilisation and Embryology Authority (HFEA) has already agreed in principle.

Opponents say that the test is unethical because it involves destroying some embryos that would never contract these conditions if allowed to develop into children. Even those that did become ill could expect many years of healthy life first.

Some critics fear that the tests move society farther down a slope that will lead ultimately to the creation of “designer babies” chosen for looks or intelligence.

However, the first patients say that the technology will allow them to spare their children a devastating genetic inheritance. One couple in their twenties, who would only be named as Matthew and Helen, have lost three generations to breast cancer.

Last May, the watchdog ruled it acceptable for doctors to screen embryos for genes such as BRCA1, which raise the risk of cancer in adulthood by between 60 and 80 per cent. Embryo screening was previously restricted to genes that carry a 90 to 100 per cent chance of causing disease.

The application is the first to be made under the new regime after a year of research to identify the precise mutations that affect Mr Serhal’s patients. Approval is likely in three to four months, once the HFEA has confirmed that the tests are reliable.

Women with a defective BRCA1 gene also have a 40 per cent risk of ovarian cancer. It is linked to prostate and breast cancer in men, who can also inherit it benignly and pass it on to their daughters.

Mr Serhal said that objections to screening ignored the harrowing family histories of the patients he is seeking to help, who have a chance to ensure their children avoid similar experiences. “We are talking about a killer that wipes out generation after generation of women,” Mr Serhal said. “You can have a preventive mastectomy, but this is traumatic and mutilating surgery that does not eliminate the risk.

“What we are trying to do here is to prevent this inherited disease from being a possibility in the first place. At least with these people’s children, we can annihilate the gene from the family tree.” Genes have also been identified that raise

the risk of conditions such as obesity, heart disease and mental illness. However, more than one gene is usually involved and the HFEA will not currently approve screening for these.

Supporters of screening point out that patients must use IVF even if fertile, and that many couples carrying defective genes will not choose this option. The HFEA code of practice also makes it clear that screening is allowed only for serious conditions.

When the licence is awarded, the couples will have IVF. This will allow a single cell to be removed from the embryo at the eight-cell stage, and tested for the defective BRCA1 gene. Only unaffected embryos will then be transferred to the womb.

Though the HFEA decided last May to accept applications to do this, after a public consultation was supportive, it has taken Mr Serhal’s team a year to develop a robust test for the specific mutations in the gene that each family carries.

The HFEA will not reconsider the ethics of screening, but will ask independent experts to review the reliability of the tests before awarding a licence. “We are very confident because the HFEA has already said in principle that this is OK,” Mr Serhal said.The HFEA said: “Each application for conditions such as this must be considered on a case-by-case basis because of the difference in the way that families are affected by these conditions.”

Josephine Quintavalle, of the embryo rights group, Comment on Reproductive Ethics, said: “There has to be a better way of curing disease than this. It is very likely that in the not-too-distant future there will be a way of treating breast cancer that doesn’t rely on eliminating the carrier instead of curing the disease.”

Last year, The Timesrevealed the conception of Britain’s first “designer baby”, screened as an embryo for inherited cancer. The baby has since been born healthy, free from the gene carried by her mother that would have given her a 90 per cent chance of developing retinoblastoma, an eye tumour.

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