News > Three-parent babies

The House of Lords has approved controversial IVF procedures aimed at preventing inherited mitochondrial diseases.

Over the last couple of months we have heard a lot of different views regarding the use of “three-person IVF” in the UK. Some people are all for it and others against it. What about you? Yes? No? Or maybe you would really like to understand what this actually is and what it means!

Babies conceived through this IVF technique would have biological material from three different people – a mother, father and a female donor.

Mitochondria are small structures inside cells that provide the cells with energy. They have their own set of 37 genes which are separate from the 20,000 or so genes in the cell nucleus that shape who we are. Everyone has mitochondria in their cells, however only mothers pass them on to their children.

So it is the woman who passes down the mitochondrial DNA and may have a few faulty mitochondria without knowing as there are no symptoms. This may not affect her but when she becomes pregnant, her eggs would carry various amounts of faulty mitochondria so her baby may be born with a mitochondrial disease. Faulty mitochondria have been linked to very serious life threatening conditions.

So in simple terms this new treatment, mitochondrial donation, replaces a small amount of faulty DNA in a mother’s egg with healthy DNA from an egg donor. Any baby would then inherit genes from two mothers and one father preventing certain genetic conditions being passed on.

Technically the baby would have three biological parents, with 99.8% of genetic material coming from the mother and father and 0.2% coming from the mitochondrial donor.

The illustration below explains the process: