Chinese researchers are challenging the notion that a woman has all of her egg cells from birth and will never create new ones. Scientists have produced new female eggs using stem cells, a development scientists say could help infertile women.

Researchers in China say it may be possible one day for women to turn back their biological clocks by repopulating their ovaries with new eggs using stem cells.

In an experiment described in the journal Nature Cell Biology, scientists at Shanghai Jiao Tong University found stem cells in mice ovaries that could be extracted, cultured and injected into sterile mice that then produced healthy offspring.

The research, which now needs to be duplicated in other labs, holds the possibility that women can produce new eggs. According to scientists, that could extend female fertility by resetting a woman's biological clock.


David Albertini, an expert on reproductive sciences at the University of Kansas Medical Center, says the Chinese research shows promise for women who are unable to conceive.

"So the very nature of the experiments in some ways parallels the human condition that many of us are interested in addressing," he said. "That is, 'What would happen to a young woman who lost many of her eggs as a result of cancer treatment, and is there a potential avenue for therapy or retaining that fertility or restoring that fertility that could draw on the power of stem cell technology?'"

But Albertini cautions that more research is needed to determine whether the procedure will work in women.

"Of course, these experiments were done in mice and for, I believe, the field of biomedical science to truly accept this as even a possibility in animals, these experiments need to be repeated because they've only been done once and they've been done under a variety of very unusual conditions. And if there's no chance of reproducing this finding in the mouse, then, obviously, we wouldn't be in a position to try this is [in] cancer patients or menopausal women," he said.

Nonetheless, David Keefe, Chairman, Department of Obstetrics and Gynecology at University of South Florida, says there may be reason for optimism for women past their childbearing years. 

"The clock can be reset and that's cause for optimism. There's everyday new ways in which we can reprogram cells," he said.

But Dr. Keefe cautions that the fertility of mice is dramatically different from human fertility and that women should not get their hopes up that the Chinese experiments will yield treatments for women anytime soon.