MPs voted overwhelmingly in support of mitochondrial donation, which is when DNA from three people is combined and put into one IVF embryo.
A total of 382 MPs voted in favour; 128 were against the technique.
This new law means that if parents have faulty mitochondrial DNA, they can use the DNA from another person to replace the non-functioning mitochondria, so that the baby doesn't inherit disorders. Around 2,500 women in Britain are thought to be at risk of passing on mitochondrial disorders to their children.
No cure for mitochondrial disease
Mitochondria are found in every cell in the human body except red blood cells. Their job is to convert energy to power the cells.
Mitochondria have their own DNA, the instructions needed to build the mitochondria so they can feed the cells, essentially powering the body and brain. But if the DNA is faulty, they don't function properly, which can lead to disorders in the vital organs.
Congratulations to all the people who have worked so hard on mitochondrial donation. It has passed in the House of Commons.— Wellcome Trust (@wellcometrust) February 3, 2015
The amendment to the 2008 Human Fertilisation and Embryology Act will now be passed to the House of Lords. The law will come into affect in October. Health Minister Jane Ellison told MPs that "for many families affected, this is the light at the end of the tunnel".
Hailed by some as a victory for medical research, it was also opposed on principle by the Catholic Church and on safety grounds by the Church of England.
Why the opposition to 3-parent babies? And y from the church?! Mitochondrial donation will end some vile diseases and relieve much suffering— Dr Christian Jessen (@DoctorChristian) February 3, 2015
Dr Jeremy Farrar, Director of the Wellcome Trust which funds the research at Newcastle University and the Wellcome Trust Centre for Mitochondrial Research, said: "Families who know what it's like to care for a child with a devastating disease are best placed to decide whether a mitochondrial donation is the right option for them.
"We welcome this vote to give them that choice, and we hope that the House of Lords reaches a similar conclusion", says Dr Farrar.
"This is a vote of confidence in the patients, scientists, doctors and ethicists who have worked hard for a decade to explain this complex research to politicians, the public and the media".
If passed by the House of Lords, the first ‘three-parent' baby could be born next year.