The UK has now become the first country to approve laws to allow the creation of babies from three people.
The modified version of IVF has passed its final legislative 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.
The first baby could be born as early as 2016.
A large majority of MPs in the House of Commons approved "three-person babies" earlier this month.
The House of Lords tonight rejected an attempt to block the plan by a majority of 232.
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.
- March to August - The UK fertility regulator will develop and then publish their licensing rules for assessing applications to perform three-person IVF
- Early Summer - The team in Newcastle publish the final safety experiments demanded by the regulator
- 29 October - Regulations come into force
- 24 November - Clinics can apply to the regulator for a licence
- By the end of 2015 - the first attempt could take place
In the debate, health minister Lord Howe said there was an opportunity to offer "real hope" to families.
He stated the UK was leading the world and that three safety reviews by experts suggested it would be safe.
Lord Howe told the House: "Families can see that the technology is there to help them and are keen to take it up, they have noted the conclusions of the expert panel.
"It would be cruel and perverse in my opinion, to deny them that opportunity for any longer than absolutely necessary."
Lord Deben, the former government minister John Gummer, countered that there were "real doubts about safety".
He also voiced concerns about whether the creation of such babies would be legal.
"It is quite clear that there is considerable disagreement, let me put it simply like that, about whether this action is legal under European law."
Baroness Scotland of Asthal, a former Labour attorney general, also questioned the legality asking: "Why the haste?
"Everyone agrees we have to get this right. If we're going to do something which everyone agrees is novel, different and important internationally we really have to be confident that we are on solid ground. If we are not we give a disservice."
Fertility doctor, Lord Winston, told the House there were comparison with the early days of IVF which was "also a set in the dark".
He added: "I don't believe my Lords, in spite of what we've heard this evening, that this technology threatens the fabric of society in the slightest bit."
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."
James Lawford Davies, a lawyer from Lawford Davies Denoon which specialises in the life sciences, told the BBC: "All of the legal arguments made in opposition to the regulations are hopeless.
"The regulations do not breach the Clinical Trials Directive which applies only to medicinal products.
"The regulations do not breach the EU Charter of Fundamental Rights and Freedoms which prohibit 'eugenic practices' as this is intended to prevent practices such as forced sterilisation and reproductive cloning, not treatments intended to prevent the transmission of disease."
The Catholic and Anglican Churches in England said the idea was not safe or ethical, not least because it involved the destruction of embryos.
Other groups, including Human Genetics Alert, say the move would open the door to further genetic modification of children in the future - so-called designer babies, genetically modified for beauty, intelligence or to be free of disease.
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.