Mitochondrial replacement: ‘three-parent IVF’

Some serious conditions are inherited not from the DNA in the nucleus, but from the mitochondria — the cell’s ‘power plants’. Mitochondrial replacement was designed to prevent them.

The popular term ‘three-parent IVF’ is striking, but can be misleading.

What are mitochondria and why do they matter?

Mitochondria have their own tiny DNA and are inherited only from the mother. Faults in it can cause severe, often incurable diseases in children.

What does mitochondrial replacement do?

The mother’s nuclear genetic material is transferred into a donor egg that has healthy mitochondria and whose nucleus has been removed. So the child inherits its parents’ traits, but healthy mitochondria.

Why do we say ‘three parents’?

Because the donor’s mitochondrial DNA is added. In practice this is a tiny fraction of the total DNA — the core inherited traits come from the two parents.

Where is it allowed, and for whom?

It is permitted in very few countries, under strict licensing, and only to prevent serious mitochondrial diseases — not as a general way to improve fertility.

The key message

It is a specialised technique for a rare group of families with mitochondrial disease, not a widely available IVF option.