By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) - The phrase ‘my biological clock is ticking’ is closely linked to the well known medical fact that women have a certain limited number of eggs made by the ovary and once they are used up there are no more and the ability to have children is finished.

Researchers in both England and at Mass General believe women may produce eggs throughout life.

The work was done on studies of mice but they found evidence that under experimental conditions the continued production of eggs maybe possible. This was research in mice and it is an assumption it could happen in humans, but you can be certain studies will continue.