Scientists from the UK’s Newcastle University have won a license from the Human Fertilisation and Embryology Authority to develop embryos with genetic material from three individuals – two mothers and one father – by transferring fused egg and sperm into another woman’s egg.

The groundbreaking research, which as expected for such a sensitive subject has come in for strong criticism, aims to prevent mothers passing mitochondrial diseases on to their unborn babies. Mitochondria convert the food we eat into energy and – uniquely – have their own DNA, separate from that found in the nucleus. Mitochondrial genes are inherited only through the mother who may pass faulty DNA on to her children. At present, no treatment for mitochondrial diseases exists.

Mice studies have shown that it is possible to prevent this transmission by moving the pronuclei (that ultimately develop into an embryo’s nucleus DNA) from an egg containing bad mitochondria to another egg containing only good mitochondria. The researchers hope to replicate this finding using human material.

The application was originally rejected under the Human Fertilisation and Embryology Act that prohibits “altering the genetic structure of any cell while it forms part of an embryo.” However, at appeal, the committee heard new evidence from leading geneticists and, in a statement, said it had “satisfied itself” not only that the research could be permitted but that it was “necessary” to use embryos.