This technique, tested on 22 women at high risk of passing on mitochondrial genetic disorders, resulted in eight successful pregnancies, with one woman still pregnant and no miscarriages reported.

The births, documented in the New England Journal of Medicine, are part of a regulated process in the UK, where 35 patients have been approved to use this method as of July 2025.

The procedure involves transferring nuclei from a mother’s fertilized egg into a healthy donor egg, replacing defective mitochondria, and has shown to significantly reduce mitochondrial DNA mutations in newborns.

Experts highlight the method's importance, noting it expands reproductive options for couples unable to avoid genetic diseases through traditional testing, and emphasizes its scientific significance.

While the children are generally healthy, some experienced minor complications, such as elevated levels of abnormal mitochondria or high blood fat, but these are not currently considered health risks.

The contribution of donor DNA is minimal, less than 1%, and does not influence traits, ensuring the children inherit their genetic makeup primarily from their parents.

The UK legalized mitochondrial donation in 2015, making it the first country to permit such research, while the US still prohibits clinical use due to concerns about heritable genetic modifications.

In the US, regulations currently prohibit similar techniques, with ongoing debates about potential future changes to restrictions on heritable genetic modifications.

The UK’s legal framework change in 2015 and subsequent regulations have facilitated this research, contrasting with the US, where such practices are banned.

Defective mitochondria, inherited only from mothers, can cause severe health issues like blindness and seizures, affecting approximately 1 in 5,000 people.

Leading experts praise the technique as a major scientific breakthrough, offering hope to families burdened by mitochondrial diseases, with ongoing assessments planned for the children’s development.

In a groundbreaking development, eight babies have been born in the UK using a pioneering three-person IVF technique called mitochondrial donation, aimed at preventing mitochondrial diseases.