LONDON (AFP) - The British government said on Friday it would pursue a radical fertility technique that uses DNA from three parents to create an embryo, setting the stage for it to become the first country to offer the treatment.

The IVF-based technique is designed to avoid serious mitochondrial diseases inherited on the maternal side, such as muscular dystrophy and cardiac problems.

Mitochondria are the structures within cells that convert energy from food into a form that the body can use.

The technique would replace some of the unhealthy DNA with healthy DNA from the so-called "third parent".

"It's only right that we look to introduce this life-saving treatment as soon as we can," said Sally Davies, the chief medical officer for England.

Parliament is due to debate the regulations next year, leading the way for Britain to offer the treatment to at-risk women. One in 200 children is born each year with a form of disease in their mitochondrial DNA.

Scientists are developing a technique to remove some of the mitochondrial DNA of the mother and replace it with DNA from the "third parent" to create a healthy embryo.

Transmitted through the maternal line, mitochondria only carry a few dozen genes, or about 0.1 per cent of the DNA code, and are separate from the nucleus of the cell which contains the remainder.

However, when mitochondrial genes carry a defect, the impact on health can be huge. Eye disorders, cardiac malfunction, diabetes, gastrointestinal and muscular diseases and even forms of dementia can result.

According to a "conservative" 2010 estimate by Patrick Chinnery, a geneticist at Newcastle University in northeast England, mitochondrial disease occurs in more than one in 10,000 people.

The idea of the therapy is to avert this by swapping the faulty mitochondria in an egg with healthy mitochondria from a donor, and then fertilise the reconstructed egg with sperm from the would-be father, following the now-classic procedures of in-vitro fertilisation (IVF).

Professor Robin Lovell-Badge, Head of Developmental Genetics at the Medical Research Council's National Institute for Medical Research, hailed the development.

He said it was "excellent news for women at risk of having children with severe mitochondrial disease due to mutations in mitochondrial DNA".

"There is nothing in the science conducted to date to suggest that the new techniques are unsafe, indeed when considered in the context of what happens to children born with these diseases, it is difficult to imagine that the new techniques will be anything but a better option to allow these women to have their own genetic offspring," he said.