A baby has been born from an egg matured in the laboratory for the first time. The egg was frozen, thawed, and finally fertilised before being kept in simulated conditions to allow its development and eventual birth.
The news has provided scientists with new data, as until now they could not say with any certainty whether or not eggs could survive after freezing and thawing to be fertilised successfully.
Scientists now say that the development may prevent women from the risk of having to take a fertility drug that can cause a rare, but deadly condition - ovarian hyperstimulation syndrome (OHSS).
The announcement was made in Lyon, France, by Canadian researchers, who added that three more babies were due soon by the same process.
They revealed that the new developments mean patients with cancer-related fertility problems may have new hope.
As women with cancer prepare for chemotherapy - a treatment that can cause infertility - patients may now be offered to have their eggs collected and frozen for future treatment in case they encounter problems.
However, some sceptics have pointed out that many will not want to delay starting their chemotherapy treatment to go through the process of ovarian stimulation - the process to extract eggs from the woman in preparation for their freezing.
It was also highlighted by Dr Hananel Holzer and colleagues at the McGill Reproductive Center, Montreal, that the technique they used - in vitro maturation (IVM) - had not yet been tried on women with cancer.
The studies they carried out were on women with polycystic ovarian syndrome (PCOS), a condition in which ovaries are overwhelmed by cysts, impairing their fertility.
The results of the study showed that of 20 women, four achieved pregnancy.
Dr Laurence Shaw, a spokesman for the British Fertility Society, told the BBC: "These pregnancies are an exciting step. However, the pregnancy rate is very low and therefore large numbers of eggs would be needed."
He also stressed that it was a treatment suitable for people with fertility problems linked to conditions such as PCOS or cancer, and was not for women who merely want to delay having a family.
