London: Britain could create history today by becoming the first country to legalise children conceived with DNA from three parents, a contentious step that has polarised opinion among activists and religious figures.

British MPs will hold a crucial vote in Parliament to decide whether to allow the creation of IVF babies using DNA from three people - mother, father and a female donor.

The technique is aimed at preventing deadly genetic diseases being passed from mother to child and is expected to help about 150 couples a year. However, the move has sparked a fierce ethical debate with senior Church figures calling for the procedure to be blocked.

If there is a "yes" vote in the House of Commons, then the first 'three-parent baby' could be born as soon as next year. The UK government backs the measure in principle but all MPs will be given a free vote rather than being forced down party lines as it is an issue of conscience.

They will be voting on mitochondrial DNA (mDNA) donation techniques aimed at preventing serious inherited diseases. mDNA is passed on through the mother and hereditary mitochondrial diseases affect major organs and cause symptoms ranging from poor vision to diabetes and muscle wasting.

Under the proposed change to the laws on in-vitro fertilisation (IVF), as well as receiving normal "nuclear" DNA from its mother and father, the embryo would also include a small amount of healthy mDNA from a woman donor.

Experts believe that the use of mDNA from a second woman could potentially help around 2,500 women in Britain at risk of passing on harmful mDNA mutations. But the Catholic and Anglican Churches in England believe the idea was not safe or ethical.