A medical team in the United Kingdom successfully used a new reproductive technique to allow eight healthy babies to be born without mitochondrial diseases. The findings were reported on July 16, 2025, in the New England Journal of Medicine. The method aims to prevent mothers from passing rare and devastating mitochondrial diseases to their children. These diseases, caused by damaged mitochondria, can lead to severe health problems such as muscle weakness, seizures, organ failure, and fatality. The use of this technique received official approval in the United Kingdom in 2016. Australia has also legalized the method, while it continues to be banned in multiple countries, including the United States. According to the study, scientists applied the procedure to fertilized embryos from 22 patients, leading to the birth of eight babies without signs of mitochondrial disease. One additional pregnancy is ongoing.

The technique is called mitochondrial replacement therapy. It involves transferring the mother’s DNA into a healthy donor egg that contains functioning mitochondria, while the donor’s original genetic material is removed. This advanced procedure creates an embryo that carries genetic material from three individuals: the mother, the father, and a donor. According to scientists, the donor DNA represents less than 1% of the baby’s total genetic composition, which means there is no risk of inheriting physical traits from the donor. Experts described the achievement as a “triumph of scientific innovation,” stating that it offers a new solution for families affected by severe genetic risks. However, some experts have warned about possible long-term consequences for future generations due to the heritable nature of the modification. In the United Kingdom, each case must receive approval from the Human Fertilisation and Embryology Authority before treatment can proceed.