An end to infertility?

Hope for women as scientists produce mice without using female eggs... and it could let two men have their own baby

BABY animals are being created without the need for eggs from a female.

Instead the eggs are grown from skin cells, fertilised in a laboratory and implanted into the mother.

The fertility breakthrough – hailed as ‘remarkable’ by British experts – gives hope that the method could be used in humans to help infertile women have babies.

But it also raises the prospect of babies being created using genes from two men, although such an embryo would still need to develop in a womb.

Japanese scientists developed the method using mice. Tissue cells from the tip of a mouse’s tail were reprogrammed as stem cells and turned into eggs, which were fertilised and implanted in female mice. They went on to give birth to 11 healthy pups, the scientists reveal in the journal Nature.

It is the first time the stem cells have been used to create mature eggs outside a mouse’s body. If the process can be made to work for humans, it could eventually offer hope to women who are infertile, for instance as a result of cancer treatment.

But Jacob Hanna, a stem cell biologist at the Weizmann Institute of Science in Rehovot, Israel, and a gay rights activist, said that the approach could also one day mean eggs are produced from a man’s skin cells – doing away with the need for a woman’s egg cells.

Professor Hanna, who was not involved in the research, said such a method, giving a baby two biological fathers but no biological mother, was ‘legitimate to explore when the right time comes,’ Nature.com reported.

Such a prospect is years away, however, experts admit.

The researchers, led by Professor Katsuhiko Hayashi at Kyushu University, used cells from the tips of mice tails to create pluripotent stem cells, which have the ability to transform into many different tissues.

The stem cells were treated with a specific cocktail of chemicals and biological signals, including mingling them with gonadal somatic cells, taken from mouse embryos, which aid egg development.

The researchers say that although the somatic cells had to be taken from an embryo they expect these, too, might eventually be developed from skin cells. Once this is done, there would be no need for any embryonic tissue. Although only 11 of 316 embryos the researchers created in the lab resulted in live births, British scientists working in the same field praised the achievement.

Martin Johnson, professor of reproductive sciences at Cambridge University, described the research as remarkable, while Professor Richard Anderson, of the University of Edinburgh, said: ‘This is the first report of anyone being able to develop fully mature and fertilisable eggs in a laboratory setting right through from the earliest stages of oocyte [egg] development.

‘Although we are a long way from making artificial eggs for women at the moment, this study also provides us with a basis for experimental models to explore how eggs develop from other species, including in women. This is extremely challenging at the moment due to the difficulties of getting eggs to study.

‘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.

‘But the very careful analyses in this paper show the complexity of the process and how it is a long way from being optimised.’

Professor Robin Lovell-Badge, from the Francis Crick Institute in London, said the work ‘should be considered as a beginning, albeit a very promising one, and not an end’.

He added: ‘Clearly, if applied to humans [the method] would have importance in overcoming female infertility but it also opens up many other uses in research, in regenerative medicine, and potentially in avoiding genetic disease.’

But there are ‘still many practical and ethical challenges to be resolved’, he said.