Scientists claim to have, for the first time, created viable artificial sperm using stem cells, a major breakthrough which they say could lead to new treatments for infertile men.
A team at Kyoto University in Japan has created the sperm producing germ cells in a laboratory and transferred them into infertile mice, which after the treatment were able to produce healthy offspring, 'The Daily Telegraph' reported.
The development could help thousands of infertile men become fathers if the method proves similarly effective in humans, say the scientists.
In fact, they used stem cells from mouse embryos to create primordial germ cells, which drive the production of sperm in men. When transplanted into testicles of infertile mice, the cells produced normal-looking sperm.
The team, led by Dr Katsuhiko Hayashi, injected the sperm into mouse eggs and implanted them into female mice, which give birth to healthy pups. The babies, when they grew up, were capable of reproducing naturally.
Previous experiments to make sperm from embryonic stem cells have not been so successful, and in most cases led to unhealthy offspring which soon died.