Human embryonic stem cells have been coaxed in the lab to develop into the early forms of cells which eventually become eggs or sperm, UK researchers reveal.

It might one day be to allow people who cannot produce eggs or sperm to have children, by taking cells from their body, deriving embryonic stem cells via therapeutic cloning and then deriving eggs or sperm.

Being able to derive eggs in the lab would also solve one of the major problems with using therapeutic cloning for treating diseases, which is that large numbers of human eggs are required.