Britain's fertility regulator could allow doctors to create the first babies to have three people's DNA from next April after the government pressed ahead with plans to legalise the procedure.
The technique, known as mitochondrial transfer, offers hope to families affected by a wide range of diseases, such as muscular dystrophy, caused by faulty DNA being passed down from mother to child.
The experimental procedure replaces faulty genetic material found in mitochondria, the small cellular batteries that power human cells, with healthy DNA taken from a donor woman.
One in 6,500 children in Britain each year are born with a serious mitochondrial DNA disorder. Many of the conditions affect power-hungry organs such as the brain, muscles and heart, and often worsen with age. Many children are disabled and die young from their illnesses.
The Department of Health announced plans on Tuesday to press ahead with regulations following a three-month public consultation which drew 1,850 responses. The draft regulations are due to go to parliament for debate in the autumn, and could be law by April next year.