The brave new world for women who want a career and then a baby later may be shaped by scientists like Roger Gosden.

The British-born professor who recently moved to the US has been pioneering the removal, freezing and eventual reimplantation of ovarian tissue and whole ovaries. While his work is aimed at benefiting women who face cancer treatment that will destroy their ovaries, it could also change society.

A baby girl is born with all the eggs she will ever have. Once has passed menarche, she will shed one a month as she ovulates. The younger the eggs, the more likely they are to fertilise and implant in the womb successfully.

Prof Gosden, scientific director of the Jones Institute for Reproductive Medicine at the Eastern Virginia Medical School in Norfolk, Virginia, carried out the first transplant of ovarian tissue on a dancer from Arizona, Margaret Lloyd-Hart, but it was of limited success and did not restore her fertility. Earlier this year, however, he revealed that he had successfully removed and frozen the ovaries from rats and reimplanted them. Two of the rats became pregnant.

He believes the same operation could take place in women in a few years' time. While its prime aim now is to help those who face radiotherapy, in the future women in their 20s may want to remove and freeze one of their ovaries in order to have a child later in life, in their 40s.

Demand for fertility treatment is high among women over 35. Some will have tried for years to have a child, but others will have put off the idea because of the demands of a career, or because they did not meet the right partner earlier.

The options at the moment are not brilliant. In-vitro fertilisation, otherwise known as test-tube baby treatment, is a gamble for anyone. Only one in six treatment cycles is successful on average. The success rate drops with age.

There are techniques that can increase the odds, such as gamete intra-fallopian transfer, in which eggs fertilised in a laboratory test-tube are placed in the fallopian tube rather than directly into the womb.

But nothing is certain in the fertility treatments currently available. The waiting and wondering are agonising and the cost can be enormous.