Mitochondrial donation will become legal in Australia, with a controversial bill passing the Senate after a conscience vote.
A bill to allow the technology under what is called "Maeve's Law", was passed by 37 votes to 17 last night.
The law is named in honour of a little girl named Maeve Hood, who has severe mitochondrial disease.
Advocates, from affected families to scientific heavyweights, are celebrating the decision.
But other experts are calling for caution, with some arguing the decision to legalise the technology was premature.
Federal Health Minister Greg Hunt was a vocal supporter of the bill.
In a statement posted on Twitter on Wednesday evening, he acknowledged Maeve and her mother, Sarah, who live in his electorate and inspired the bill.
"It is globally leading mitochondrial legislation to give hope to families across Australia," Mr Hunt said.
Advocate David Thorburn, a mitochondrial researcher at Murdoch Children's Research Institute, welcomed the decision.
"Mitochondrial diseases impact on at least one child born in Australia each week," Professor Thorburn said.
"Affected patients typically suffer severe disease affecting their brain, heart or other organ systems and early death, ranging from infancy to middle age.
Professor Thorburn said the bill will protect against misuse of the technology.
"The regulatory environment has safeguards that will ensure it can only be used for the intended purpose and the reforms are consistent with international standards and best practice."
But mitochondrial genetics researcher Jus St. John at the University of Adelaide expressed concerns.
"The Australian Parliament has taken a large step into the unknown," he said.
His lab is currently trying to determine how safe mitochondrial donation is.
"If it is safe and there are no side effects, then I would be happy for it to be implemented, but until we are absolutely sure, then I have big reservations about its use," he said.
"We do not have sufficient data from large animal models that are similar in their embryology, physiology, etc to humans.
"The passing of this legislation is at least five years too early and we should wait until the data are available to validate or otherwise the technology."
Catherine Mills, director of the Monash Bioethics Centre at Monash University, described the decision as "an important step forward", but stressed there were ethical issues ahead.
"We also need to keep in mind that there is still a lot of work to be done to ensure that the actual implementation of mitochondrial donation in Australia is done in an ethically robust way," she said.
"It is important to ensure that this appropriately balances the interests of all stakeholders, including parents, oocyte [egg] donors, and the children that may be born using this technology."
