The UK fertility watchdog today approved extending embryo screening to cover a wider range of inherited diseases.
The move by the Human Fertilisation and Embryology Authority means clinics would be able to screen couples with a family history of certain types of cancer.
The ruling means embryo testing should be used to identify those at risk of developing breast and ovarian cancer caused by mutations of the genes BRCA1 and BRCA2 respectively, and a type of colon cancer called HNPCC.
The authority has already licensed the test, known as pre-implantation genetic diagnosis, for some inherited cancers, such as a type of bowel cancer called FAP, and cancer of the retina.
The technique has previously been used to screen for cancers that affect young adults or children. But the extension of testing would allow it to be used to screen for diseases that would not affect somebody until they were in their 30s or 40s.
BRCA1, BRCA2 and HNPCC both result in about an 80% risk of developing cancer while BRCA1 carriers also have a 40% risk of developing ovarian cancer. But the move to extend embryo screening raises ethical questions because these cancers are not certain to develop and are potentially treatable. The decision, which was made at a meeting of the fertility watchdog in Belfast, will be reviewed in 2008.
Dame Suzi Leather, chairwoman of the authority, denied the move paved the way for extending screening to a much wider range of conditions in the future.
She said: "The decision today deals only with serious genetic conditions that we have a single gene test for. We would not consider mild conditions - like asthma and eczema - which can be well-managed in medical practice. We would not consider conditions like schizophrenia where a number of genes have been identified but there is no single gene that dictates the condition.
"This is not about opening the door to wholesale genetic testing. This is about considering a particular group of genetic conditions to be sufficiently serious to merit the use of PGD embryo testing. These genetic tests can still only be used for a minority of people if there is a clear history of cancer across generations of a family."
Dr Vivienne Nathanson, head of ethics and science at the British Medical Association, said: "We do not see that today's decision is moving towards 'designer babies'. There is a world of difference between a parent not wanting their child to develop breast cancer and someone wanting a child with blue eyes and blond hair. We do not believe parents will undertake embryo selection for trivial reasons and we do not believe they should be allowed to do so."
