"The normal age for menopause is the subject of debate but experts consider early menopause to be before the age of 45. Possible reasons include chromosome abnormalities, such as a woman with Down's syndrome; enzyme deficiencies, where enzymes damage eggs and prevent the production of the hormone oestrogen; and auto-immune diseases, where the body effectively turns on itself. Today, scientists at the World Congress of Fertility and Sterility in Munich said their latest work in rats could offer hope for the future. A team from Cairo University in Egypt used stem cells to restore ovarian function in a group of 60 female rats."