In a world first, members of the UK parliament have voted to allow mitochondrial donation.

The procedure will allow women with genetic faults in their mitochondria – the cell’s energy generators – to have children without fear of passing on their faulty mitochondrial DNA. It involves transferring the nucleus of the mother’s egg or fertilised embryo into an egg from an unrelated donor. The resulting child will inherit their nuclear DNA from their parents and their mitochondrial DNA from the donor. Because the change to the mitochondrial DNA is permanent, the technique will not only prevent the child inheriting mitochondrial disease but also any of their descendants.

The vote passed with 382 in favour and 128 against. During the preceding debate, health minister Jane Ellison told parliament: “This is a bold step but it’s an informed step, and for the families involved it’s a light at the end of a very long tunnel.”

The shadow health minister Luciana Berger also threw her weight behind the procedure, saying: “There will always have to be a leap of faith the first time it’s used in humans… but I believe we must not delay any further.” The former Minister for Universities and Science David Willletts emphasised to MPs that mitochondrial DNA does not play a role in shaping the character or personality of the person. “The red line is where we change the nuclear DNA,” he said.


Among others, dissent came from the Conservative MP Fiona Bruce who worried that the genetic alterations will be passed down to future generations – “once the alteration has taken place, there is no going back, for society or the children involved,” she said.

One potential beneficiary is Hannah Smith, a 27-year-old woman from Measham, Leicestershire, who has a mitochondrial mutation causing Melas Syndrome, which can causes diabetes, hearing loss and epilepsy. “I’m of a child-bearing age and it couldn’t have come at a better time,” Smith told New Scientist. “It means I can live a normal life, my children can live a normal life and their children can live a normal life.”

No evidence it is unsafe

At a public debate last night, Andy Greenfield, a member of an independent panel convened by the UK Human Fertilisation and Embryology Authority (HFEA) to advise the government, revealed that new, unpublished data gave added reassurance that the procedure would be safe. The research was carried out by a team at Newcastle University, UK, that has been pioneering one of the replacement techniques since 2000.

Their new work comes on the back of three scientific reviews, an ethics review and a public consultation overseen by the HFEA. Frances Flinter, professor of genetics at King’s College London, told the debate: “We can’t guarantee the intervention will be safe, but we can tell couples that we have no evidence it will be unsafe.”

The Newcastle group estimates that the procedure could help 2473 women in the UK, and 12,423 women in the US, aged between 15 and 44 years. This equates to an average of 152 births per year in the UK, and 778 births per year in the US.