Three-parent embryos created

Scientists in the US have made medical history by creating human embryos with three parents. This is a step towards using IVF techniques to solve so-called mitochondiral diseases, caused by faulty 'power stations', or mitochondria, in a mother's egg cells.   Because an embryo's mitochondria are only provided by the egg cell, researchers think that transferring the nucleus from an egg with faulty mitochondria into a donor egg with functional ones could sidestep the disease and create healthy babies. Writing in the journal Nature, Dr Shoukrat Mitalipov and his colleagues took the nucleus, containing DNA, out of human egg cells and transferred them into egg cells that had had their nucleus removed. These composite eggs were then fertilised by human sperm, and allowed to start developing.

This technique has already been successfully used in monkeys, leading to the birth of healthy monkey babies, and these new results show that it's potentially feasible in humans, although the embryos were destroyed after only a few days, when they were just a small cluster of cells. The UK recently launched a consultation on whether to consider the technique for treating patients with mitochondrial diseases, and this new study answers some questions about whether the technique could actually work in huma