News

12th March 2004

Possible extension to female fertility

Scientists say that they may have got a basic rule of female anatomy wrong and if so, it could raise fertility hopes for thousands.

For nearly 100 years, doctors have believed that women are born with a set number of eggs and when those eggs run out, the menopause begins. But researchers at Harvard Medical School have found that female mice continue to produce eggs after they are born.

The scientists used chemicals to kill off all eggs in pre-pubertal mice and discovered that they still produced viable eggs in adulthood, proving they could therefore generate replacement eggs for damaged ones. The researchers believe the replacement eggs were produced by stem cells in the ovaries.

The findings may mean that scientists will have to re-think one of the basic rules of human biology, the researchers said. "Although this dogma has persisted for more than 50 years, the present study provides evidence that challenges the validity of this belief, which represents one of the most basic underpinnings of reproductive biology."

Chris Barratt, professor of reproductive medicine at the University of Birmingham, said of the discovery, "If you assume that the same process works in humans then this is a really big deal. I think it is probably reasonable to assume that it might be the same. There is similar ovarian development in mice as in humans."

If the pattern is repeated in humans then it could open up a whole new avenue of research into the possible treatments for female infertility and the menopause. There is a chance of extending the lifespan of the stemcells, for example, and so extending fertility.

This latest research comes at the same time as doctors in America say they successfully transplanted ovarian tissue back into a 36-year-old woman after it had been removed from the woman six years previously, prior to chemotherapy.

Writing in The Lancet, they said the woman now had fully functional ovaries. They said the technique could one day help other women to become fertile again.

• Is this taking science too far? Air your views in Your Shout
• Find out more about infertility in the Infertility section