Scientists have created fertile and mature eggs from mouse skin cells in the lab and used them to produce what appear as healthy pups.

The experiment is the first time eggs were completely made sans the help of an animal. The breakthrough may possibly herald the end of infertility as it could pave way for new treatments that would allow infertile women to have children.

Katsuhiko Hayashi, from Kyushu University, and colleagues used stem cells taken from embryos and those generated from mature cells from the tips of mouse tails. The latter were used to produce induced pluripotent stem (iPS) cells with properties of embryonic stem cells such as the ability to transform into different tissues.

Both stem cells were exposed to a cocktail of chemicals and biological signals to get them to develop into eggs. Cells from the ovaries of mouse fetuses were then placed among the immature egg cells so they can grow into mature eggs.

The researchers then fertilized some of the eggs using mouse sperm. The fertilized eggs were then implanted into the uterus of albino female mice. Eight pups were born out of the 1,348 embryos made.

Since the mammalian eggs in the experiment were produced from scratch in the laboratory, the results suggest the technique can be used in humans, which could make possible the creation of lab-made offspring.

"This culture system will provide a platform for elucidating the molecular mechanisms underlying totipotency and the production of oocytes of other mammalian species in culture," the researchers wrote in their study, which was published in the journal Nature on Oct. 17.

It may take years though before the technique can be developed to be reliable and safe enough for use in humans albeit Jacob Hanna, from the Weizmann Institute of Science in Rehovot, who has worked with a team that was able to produce immature egg cells from human skin cells, thinks it is possible that the feat can be applied to humans within five years.

If the technique works, it can be used to produce eggs for infertile women or those who have a low number of eggs to enable them to have IVF. The method may also theoretically be used to produce egg cells from male skin cells, which raises the possibility for babies with two genetic fathers.

Use of the technique, however, is likely to face hurdles such as the ethical challenges presented by the idea of making children in the lab.