'Modern twist' on fertility technique may offer hope for sterile men

Fourteen babies have been born following the injection of very immature sperm cells into eggs – a technique that could help infertile men to become fathers, scientists say.

The 14 children were born to 12 men and their partners in Japan after round spermatid injection (Rosi), which has been banned in the UK since the 1990s due to concerns for the health of any children it might create.

The disclosure that Japanese scientists have helped previously sterile men to father healthy children using the technique has prompted an expert in male fertility to call for the UK ban to be looked at again.

The method uses spermatids, which are early stage, round-shaped sperm cells that are no more than three-quarters of the way through the normal development process, have no head or tail and do not look like sperm. They can be found in the testes of men who would normally be considered sterile.

In the UK about 1% of British men are infertile because they do not produce sperm. In the Japanese trial the scientists found that...