British MPs have opted to allow "three parent babies" in a landmark vote that could see the first babies born using this technique as early as next year.
In a free vote in the Commons, 382 were in favour and 128 against the technique, which will stop deadly genetic diseases being passed from mother to child.
Ministers said the technique – which has garnered widespread criticism from some groups, who say it will lead to "designer babies" – is the "light at the end of a very dark tunnel" for families that have been affected.
Another vote is now required in the House of Lords to pass the law – if it is, the UK will be the first country in the world to allow the procedure.
Pioneered by Newcastle University scientists, the technique replaces defective mitochondria, passed down from the mother, with the healthy mitochondria of a donor woman.
It is thought the technique will help about 2,500 women in the UK. It would create a permanent change that would prevent these diseases being passed down through any more generations.
Public Health Minister Jane Ellison said: "This is a bold step for parliament to take, but it is a considered and informed step."
Prior to the vote, England's chief medical officer Dame Sally Davies said the technique will prevent huge suffering: "The 37 genes in the mitochondria are for energy making. They do not make us who we are or what we are. Yet children born with defective ones often don't live a year or two.
"Others get gradual deterioration of muscles, heart, kidneys, vision and brain and die in their late teens and early twenties."
Writing in the Telegraph, she added: "The intention in making these regulations is to ensure that mothers who carry faulty mitochondria can have healthy children free from devastating and often deadly conditions caused by serious mitochondrial disease.
"It is important to remember that mitochondrial DNA represents less than 0.054 per cent of the total DNA, and is not part of the nuclear DNA, which determines our personal characteristics and traits such as personality, hair and eye colour.
"It is only right that we introduce this life-saving treatment as soon as we can so we can give hope to hundreds of UK families."