FOR the first time, scientists have created viable mammalian eggs from scratch in the lab – and used them to produce healthy offspring.

Experts say the breakthrough could one day offer new hope to women who have lost their fertility – as a result of cancer treatment, for example.

However, it is likely to be many years before the technique – so far performed in mice – is reliable and safe enough for humans.

The scientists behind the discovery say the process could also shed light on the complexities of reproduction, and aiding the conservation of endangered species.

In the experiments, the Japanese team – led by Professor Katsuhiko Hayashi, from Kyushu University – used stem cells both obtained from embryos and generated from mature cells taken from the tips of mouse tails.

One day, this approach might be useful for women who have lost their fertility at an early age, as well as for improvements in more conventional infertility treatments

Professor Richard Anderson, from the University of Edinburgh

The latter were used to create induced pluripotent stem (iPS) cells which have the properties of embryonic stem cells, including the ability to transform into a multitude of different tissues.