Couples who have a risk of passing on an inherited form of colon cancer to their children will be allowed to have their embryos screened to ensure they do not carry the faulty gene that causes the illness.

The Human Fertilisation and Embryology Authority (HFEA), the country’s fertility watchdog, said it granted a license to University College Hospital in London to screen for familial adenomatous polyposis (FAP), a cancer that usually occurs in children in their early teens.

“At the moment we have issued a license to one hospital, University College Hospital,” a spokesperson for the HFEA said in an interview.

Fertility clinics in Britain can already screen embryos created through in-vitro fertilization (IVF) for diseases such as cystic fibrosis and Huntington’s disease. The new license is the first for an inherited form of cancer.

It will enable the hospital to screen embryos and ensure that only those free of the faulty gene are transferred to the womb.

“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 passing it on,” one of the patients who will benefit from the decision, told The Times newspaper.

Critics fear the decision will lead to doctors being able to pick and choose other diseases and apply for permission to screen embryos for them.

But Vishnee Seenundun of the HFEA said any clinic that wants to carry out pre-implantation genetic diagnosis (PGD) must obtain a license from the HFEA.

“The HFEA issues licenses for PGD where the embryo is at significant risk of developing a serious condition,” the authority said.

“All PGD applications are sent out to a minimum of two peer reviewers and decisions are taken by HFEA license committees who consider the scientific, ethical and medical information.”

FAP is an inherited condition caused by mutations in the adenomatous polyposis coli (APC) gene. Half of children of a parent with the mutated gene, which leads to the development of polyps in the colon which can turn into cancer, will inherit it.

Using PGD, doctors can genetically analyze a single cell from an embryo to determine whether it has the faulty gene.