The results are the first to indicate that the technique might work in humans

Professor John Radford

He began to produce sperm again after undergoing pioneering surgery at the Christie Hospital in Manchester, UK. Now, his wife is expecting a baby.

The procedure involved taking tissue from the patient's testicles before he started chemotherapy and freezing it in liquid nitrogen.

Two years later, with the cancer in remission, Christie experts reimplanted the testicular tissue.

John Radford, Professor of Medical Oncology at the Christie Hospital and University of Manchester, led the research team.

Not conclusive

He said: "The results are encouraging but not conclusive.

"It is not certain that the patient's recovery was caused by the operation.

The surgery took place at the Christie Hospital

"A large number of men become infertile after chemotherapy, but a very small proportion subsequently regain their fertility spontaneously.

"The results are however the first to indicate that the technique, which has already been performed successfully in animals, might work in humans. We are therefore cautiously optimistic."

The man was among seven patients to receive similar transplants at the hospital, but the only one whose fertility has been restored.

The procedure would particularly benefit prepubescent boys who cannot bank sperm before treatment, but who have sperm precursor stem cells that could be reimplanted.

It would also be useful for men who are too ill to bank sperm before chemotherapy, or who prefer a natural conception.

Clare Brown, executive director of CHILD, the UK National Infertility Support Network, told BBC News Online: "CHILD is delighted for the couple, and this success story gives us all hope for the future.

"Testicular Cancer is surprisingly common, and particularly traumatic when is detected, and findings like these which may restore fertility is great!

"CHILD awaits the results of further research with great interest."