BRITAIN could become the first country in the world to permit babies to be born with three genetic parents by the end of next year.
A landmark decision by the Department of Health opens the door to controversial treatments for inherited diseases that make use of donated DNA from a second donor "mother".
New regulations to fertility law allowing the procedures will be issued for public consultation later this year and then debated in Parliament.
If MPs find them ethically acceptable the first patients could be treated within months. It is envisaged that between five and 10 "three parent" babies would be born each year.
Allowing the currently illegal techniques would mark a turning point because it means, for the first time ever, altering the "germ line" made up of inherited DNA.
Experts point out that only the tiny amount of DNA in a cell's "battery packs", the mitochondria, would be changed. DNA in the nucleus, which determines individual characteristics, such as facial features and eye colour, would remain intact.
But some critics believe the move would mark a slippery slope leading to "designer babies" and eugenics.
The aim of the In-Vitro Fertilisation (IVF) treatments is to stamp out serious mitochondrial diseases which can be passed from a mother to her children.
Around one in 200 babies are born each year in the UK with defects in the mitochondria, rod-like bodies that supply cells with energy. One in 6,500 is seriously affected and can suffer potentially life-threatening diseases, including a form of muscular dystrophy and conditions leading to hearing and vision loss, heart, lung and liver problems, and bowel disorders. An estimated 12,000 people in the UK live with the diseases.
The new techniques result in defective mitochondrial DNA (mDNA) being replaced by a healthy version supplied by a female donor.
A recent public consultation found that 56pc of those questioned were "very" or "fairly" positive about the treatments. Patient focus group participants were said to be "extremely positive".
Experts are also behind the procedures, which are being developed in Newcastle.