This is the VOA Special English Health Report.

New research could raise hope for women who are having trouble getting pregnant.

For years, the thinking has been that women are born with all the eggs their bodies will ever produce. In fact, this has been the thinking not just about humans but all mammals.

Then, in two thousand four, a researcher at Massachusetts General Hospital reported a surprising discovery. Jonathan Tilly found that adult female mice could produce new eggs.

Now, Jonathan Tilly has extended his work and reported another discovery -- this time about human females.