In a scientific first, human eggs have been grown in the laboratory using stem cells scraped from the surface of women's ovaries and the development raises the possibility of delaying menopause and providing a limitless source of donor eggs for in vitro fertilisation treatments and embryonic stem cell research.
The researchers at the University of Tennessee, led by Antonin Bukovsky, say their findings challenge the belief that women were born with a fixed supply of eggs and can not make new ones. They say harvesting the ovarian stem cells was a comparatively simple process by using keyhole surgery.
Professor Bukovsky and his team report that they had obtained ovarian stem cells from five women aged 39 to 52. They cultured the cells for five days until they developed into eggs "suitable for fertilisation".
Professor Gesine Kogler, of the University of Dusseldorf in Germany in separate research also shows the enormous potential of adult stem cells. Researchers there have isolated a rare stem cell in umbilical cord blood that can turn into bone, cartilage, blood, nerve cells and liver and heart tissue in animals and they say these rare cord blood cells can be grown in large numbers and are a promising alternative to embryonic stem cells as a source of new tissue.
The researchers say the approach might make it possible to produce more eggs for women undergoing IVF than the present collecting of ripe eggs from the ovary and the technique is easier.
The stem cells could be used to rejuvenate the ovaries of older women and extend fertility by a decade. Young women who feared having to delay childbirth, or those facing treatment for cancer, might also be able to store their ovarian stem cells for future use.