A new row over "designer babies" has broken out after scientists called to be allowed to screen embryos for genes that might lead to cancer in later life.

Researchers want to be able to test IVF embryos for genes that can cause cancer before they are selected for implanting in the mother.

But pro-life campaigners said the issue would lead to a slippery slope where eventually all embryos are screened for even minor deficiencies.

The screening technique is already licensed for use at Newcastle's Centre for Life for some diseases but so far has not been used because the fertility unit has never been commissioned by the NHS to carry it out.

At the moment, it is allowed only for parents with a family history of conditions which will definitely be passed on to their children if the faulty gene is present, such as cystic fibrosis and Huntington's disease.

But now the Human Fertilisation and Embryology Authority (HFEA) is considering whether it should also be used to prevent children being born with faulty genes which will not always lead to diseases, including breast, ovarian and colon cancer.

If the technique is approved, doctors at the Centre for Life want their clinic to be one of two or three specialist centres nationwide to offer the procedure, known as pre-implantation genetic diagnosis (PGD).

It could also mean women who carry high-risk breast cancer genes could opt to have fertility treatment to screen them out, even if they were able to conceive naturally.

Medical director for genetics at the Centre for Life Prof John Burn said he had been calling for five years for the technique to be more widely available.

"It's just nonsense that people are going to want to choose the colour of their babies' eyes," he said.

"There's a big difference between serious genetic disorders and mythology about designer babies. At the moment, you can test a 16-week-old baby in the womb for almost anything. We are talking about testing on a handful of cells."

Prof Burn said he wanted individual doctors and families to be able to determine whether a disorder was serious enough for testing, instead of government regulation.

"We need to get away from central regulation and go down the route of local common sense," he added.

"It's good this is being thrown into the public arena because it needs further debate."

But the director of Comment on Reproductive Ethics Josephine Quintavalle said: "I'm not even sure it's ethical to be asking these questions. "We should be very alarmed at how quickly the goal posts are moving. We're talking about diseases where we're not even sure if the carrier will develop them and even if they do, it will be 30 or 40 years down the line, when there might be a cure."

Education officer for the North-East branch of the Society for the Protection of the Unborn Child, Eileen Brydon, said: "Children are not commodities."

The HFEA's policy team has been reviewing the issue since the start of the year, but has now decided to hold a wider public discussion. HFEA chief executive Angela McNab said it was only a matter of time before she had to consider applications for using the treatment in this way.

"We are asking people whether it is appropriate to use embryo-screening technology to stop children being born with faulty genes when there is a chance they may never go on to suffer the cancer," she said.

A spokesman for Cancer Research UK in the North-East said: "The issue is certainly a complex one. Carrying a faulty version of the gene BRCA1 is by no means a death sentence."

Public discussion, including a debate in Newcastle, is expected in the late autumn.