Infertile men could become fathers in latest breakthrough

A SCIENTIFIC breakthrough that resulted in the birth of healthy mice from artificially derived sperm could pave the way for infertile men to become fathers.

Fertility experts believe it may eventually lead to a process whereby sperm could be developed from skin cells or bone marrow.

A paper on the Japanese research led by Dr Katsuhiko Hayashi, from Kyoto University, appeared yesterday in the journal Cell.

British fertility expert Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, said the breakthrough was “quite a step forward in developing a process by which sperm could be made for infertile men, perhaps by taking as a starting point a cell from their skin or from something like bone marrow”.

“Clearly more work needs to be done to refine this process, but it’s hugely exciting,” Dr Pacey said.

The research on mice involved coaxing stem cells extracted from early stage embryos to become sperm precursors called primordial germ cells (PGCs).

When these cells were transplanted into newborn mice lacking their own PGCs, they continued developing to become normal-looking sperm.

The stem cell-derived sperm was then used to fertilise eggs, generate pregnancies, and produce male and female mouse pups which grew into healthy, fertile adults.

Dr Pacey said a crucial aspect of the research was that fully mature sperm were not created in the laboratory — a practise that is illegal in Britain.

“In this case you’re not technically creating sperm, so it might be that you can side-step this regulation,” Dr Pacey said.

In Ireland, there are no laws governing assisted human reproduction.

Dr Pacey said the Japenese research had “huge implications for furthering our understanding of how sperm are made, but may one day lead to a clinical application whereby we could make sperm for infertile men”.

Previous animal experiments have led to the birth of unhealthy offspring which quickly die.

Dr Pacey said one important way the technique could be used in future, if the law allows it, would be to help cancer patients.

Chemotherapy and radiotherapy for childhood cancer can wipe out a boy’s future fertility before his sperm can be frozen. In such cases, artificial methods of producing sperm may be a man’s only hope of fatherhood.

Dr Jane Stewart, spokeswoman for the British Fertility Society, said the Japanese breakthrough “marks a further step towards this goal”.

“However, as the authors clearly point out, much work remains to be done before we have a full understanding of such biological processes and indeed the implications of undertaking them in the laboratory,” she said.