A cancer patient made infertile by chemotherapy has, in a world first, given birth after revolutionary treatment, Belgian doctors say.
Tamara is the first baby to be born to a woman after an ovary transplant
Ovarian tissue from Ouarda Touirat,32, was removed and frozen seven years ago before chemotherapy, then re-implanted into her pelvis last year.
She conceived naturally and gave birth at Brussels' Cliniques Universitaires Saint-Luc this week, the Lancet reported.
The researchers said all young women with cancer should be offered the treatment.
Mrs Touirat, speaking at a press conference on Friday, said: "I'm very happy, it's what I've always wanted. It was a dream."
1) Part of Ms Touirat's left ovary removed
2) Ovarian tissue cut up and frozen in liquid nitrogen
3) Seven years later tissue was implanted near Ms Touirat's fallopian tube. It began producing eggs, allowing a normal conception to take place
Baby Tamara, weighing 3.72kg (just over 8lbs) was born on Thursday night.
A spokeswoman for the Cliniques Universitaires Saint-Luc said mother and baby were in good health.
She said: "It is the first birth ever of its kind.
"The implications are that if it has worked once it can be proposed to other women in a similar situation - woman who are suffering from certain kinds of cancer.
"When they are cured this tissue can be re-implanted and hopefully pregnancy could ensue from that. Obviously the implications for the future are great."
Lifesaving cancer treatment as a child of young adult can cause many women to go through an early menopause and become infertile. Radiotherapy is thought to be harmful than chemotherapy.
Experts stress most women who undergo chemotherapy will not become infertile. However the treatment may lead the length of time they are fertile being shortened.
Doctors across the world have been working to enable cancer patients whose fertility has been affected to become pregnant for many years.
The Belgian doctors say the fact that a successful birth has been achieved offers hope to thousands of infertile cancer patients.
The Cliniques Universitaires Saint-Luc says it has frozen ovarian tissue from 146 other cancer patients. So far, the tissue has been reimplanted in two.
Professor Jacques Donnez, who led the research into the treatment at the Catholic University of Louvain, said: "Our findings open new perspectives for young cancer patients facing premature ovarian failure."
But there are ethical implications over the treatment's potential use to beat the menopause.
Women are born with a supply of eggs - normally about a million - which die off during their lives until the menopause, when there are too few left to support a pregnancy.
The technique involves stripping a 1-2mm layer from the ovaries and cutting it into sections, which are
then frozen in liquid nitrogen at a temperature of almost -200║C.
The tissue can later be transplanted to any part of the body and still function.
Eggs can then be removed and used in IVF treatment, but in the Belgian case, the tissue was placed at the ends of the fallopian tubes allowing a natural pregnancy.
Ms Touirat had undergone chemotherapy and radiotherapy for Hodgkin's lymphoma.
Prior to the treatment, some of her ovarian tissue was removed and frozen. One ovary was left inside her body.
When she was declared cancer-free in April 2003, the ovarian tissue was transplanted back into her body, just below her existing ovary.
Four months later, she was found to be menstruating and ovulating normally.
It was revealed that she had become pregnant in June this year.
In their Lancet paper, the researchers say all the evidence they can see shows that the egg follicle, which ripened into the egg during the menstrual cycle in which Mrs Touirat became pregnant, came from the transplanted tissue.
Professor Robert Souhami, an executive director of Cancer Research UK, told BBC News Online: "What they have done is shown that they can make this treatment work.
"Having shown it in one person, they know how to do it in a second.
"And the more times it is done, the more times you are likely to have a success."
He said many thousands of women worldwide could benefit.
But he said: "What we've got to do is define which women are at the highest risk of infertility."
Simon Davies, Chief Executive of Teenage Cancer Trust says: "This is a fantastic development and offers real hope to females diagnosed with cancer."