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'Lab-made sperm' fertility hope

Scientists have proved for the first time that sperm grown from embryonic stem cells can be used to produce offspring.

The discovery in mice could ultimately help couples affected by male fertility problems to conceive.

The experiment was carried out using mice and produced seven babies, six of which lived to adulthood. However, the mice showed abnormal patterns of growth, and other problems, such as difficulty breathing.

Professor Karim Nayernia, fromNewcastle University in the UK, said: "For the first time we have created life using artificial sperm. This will help us to understand how men produce sperm and why some men are unable to do this. If we understand this we can treat infertility in men."

About 1% of all men don't produce sperm and a further 3-4% of men have a low sperm count that could lead to infertility. In the future, men with fertility problems might be able to have their own stem cells harvested using a simple testicular biopsy, matured in the lab and then transplanted back.