The UK has now become the first country in the World to approve laws to allow the creation of babies from three people.
The modified version of IVF has passed its final obstacle after being approved by the House of Lords.
The fertility regulator will now decide how to license the procedure to prevent babies inheriting deadly genetic diseases.
A large majority of MPs in the House of Commons approved “three-person babies” earlier this month.
The first baby could be born as early as 2016.
How will it work?
Mitochondria are the tiny compartments inside nearly every cell of the body that convert food into useable energy.
But genetic defects in the mitochondria mean the body has insufficient energy to keep the heart beating or the brain functioning.
The structures are passed down only from the mother and have their own DNA, although it does not alter traits including appearance or personality.
The technique, developed in Newcastle, uses a modified version of IVF to combine the healthy mitochondria of a donor woman with DNA of the two parents.
It results in babies with 0.1% of their DNA from the second woman and is a permanent change that would echo down through the generations.
Sally Cheshire, the chairwoman of the Human Fertilisation and Embryology Authority, said: “Britain is the first country in the world to permit this treatment, and it is a testament to the scientific expertise and well-respected regulatory regime that exists across the UK that Parliament has felt able to approve it.
“The HFEA now have to develop a robust licensing process, which takes into account on a case by case basis the technical and ethical complexities of such treatments to ensure that any children born have the best chance of a healthy life.
“The HFEA has a long tradition of dealing with medical and scientific breakthroughs, ensuring that IVF techniques, pioneered in the UK and now practised across the world, can be used safely and effectively in fertility treatment.”
Prof Alison Murdoch, who was instrumental in developing the technique at Newcastle University, said: “For 10 years we have publically discussed mitochondrial donation to explain how it could help patients whose families are blighted by the consequences of mitochondrial abnormalities.
“Whilst acknowledging the views of those who have a fundamental objection to our work, Parliament has determined that we should continue. We hope that opponents will accept its democratic decision.
“The science will be reviewed and, if accepted, we hope to be able to submit a treatment application to the HFEA when regulatory policies have been determined.”
Estimates suggest 150 couples would be suitable to have babies through the technique each year.
If the measure goes ahead, the first “three-person” baby could be born next year.