The doctors involved in pioneering ovarian graft surgery, with the potential to treat sufferers of premature menopause and restore cancer victims' fertility, remained upbeat about the process despite reports that the initial operation has not been as successful as was hoped. The operation, carried out in February this year, involved transplanting ovarian tissue back into a woman who had her ovaries surgically removed for medical reasons. It was hoped that Margaret Lloyd-Hart, then 29, would be able to ovulate normally once the ovary was reintroduced. However, she has had to continue relying on hormone replacement therapy nine months after the operation.

Kutluk Oktay, director of reproductive endocrinology and infertility at New York Methodist Hospital, where the operation took place, said he was pleased with the results and as far as the scientists involved were concerned, the transplant had been a success. He said that Mrs Lloyd-Hart, a professional dancer, has failed to ovulate naturally because she continued to exercise vigorously. Dr Oktay, who collaborated with Professor Roger Gosden - formerly of Leeds University and now at McGill University in Montreal, Canada - said that undue emphasis has been placed on using ovarian grafts to reverse or delay the menopause. 'The main purpose is to create a reproductive option for young cancer patients who would otherwise be sterilised through radiation or chemotherapy', he said.