Concerns about the safety of a pioneering therapy that would create babies with DNA from three people have been raised by researchers.
The advanced form of IVF could eliminate debilitating and potentially fatal mitochondrial diseases.
Writing in the journal Science, the group warned that the mix of DNA could lead to damaging side-effects.
The expert panel that reviewed the safety of the technique said the risks described would be “trivial”.
The UK is leading the world in the field of “mitochondrial replacement”. Draft regulations to allow the procedure on a case-by-case basis will be produced this year and some estimate that therapies could be offered within two years.
Mitochondria are the tiny, biological “power stations” that provide nearly every cell, which make up the body, with energy. They are passed from a mother, through the egg, to her child.
But if the mother has defective mitochondria then it leaves the child starved of energy, resulting in muscle weakness, blindness and heart failure. In the most severe cases it is fatal and some families have lost multiple children to the condition.
The proposed therapy aims to replace the defective mitochondria with those from a donor egg.