MPs have voted in favour of the creation of babies with DNA from two women and one man.
In a free vote in the Commons, 382 were in favour and 128 against the technique that prevents deadly genetic diseases being passed from mother to child.
During the debate, ministers said the technique was “light at the end of a dark tunnel” for families.
The UK is now set to become the first country to introduce laws to allow the creation of babies from three people.
A further vote is required in the House of Lords. It everything goes ahead then the first such baby could be born next year.