Babies made using three people’s DNA are free of hereditary disease

Eight children have been born in the UK using genetic material from three people, which appears to have prevented them from developing serious genetic conditions

By Carissa Wong

16 July 2025

The babies were conceived via IVF

ZEPHYR/SCIENCE PHOTO LIBRARY

Eight young children appear to have been protected from serious genetic conditions after being born using DNA from three people. The procedure involved replacing defective mitochondria from their mothers with those from a female donor.

Around 1 in 5000 people have defective mitochondria, which ordinarily provide cells with energy and are only inherited from our mothers. These defects are caused by genetic mutations that can lead to issues such as blindness, seizures and, in extreme cases, death. “It’s very difficult for families to deal with these diseases; they are devastating,” says Bobby McFarland at Newcastle University, UK.

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In 2015, the UK became the first country to approve a procedure called pronuclear transfer for women who are at high risk of passing on mitochondrial conditions and would not benefit from preimplantation genetic testing, which screens embryos for such mutations.

Pronuclear transfer involves eggs from both a would-be mother and a donor being fertilised with sperm from the father via IVF. About 10 hours later, the nucleus is removed from both eggs. This carries most of a cell’s genetic material, which is separate from mitochondrial DNA.

The mother’s nucleus is then inserted into the donor’s egg, resulting in an embryo that inherits most of its DNA from its biological parents, but mitochondria from the donor. A small amount of the mother’s mitochondria may still be unintentionally passed on, says Bert Smeets at Maastricht University in the Netherlands.