Misconceptions abound about the range and limits of female fertility. Despite concerted infertility education efforts, both the public and young women almost always are shocked to learn that female fertility starts to decline at age 27. But one to four percent of women under 40 will be faced with the even more shocking diagnosis of premature ovarian failure (POF). POF is a loss of ovarian function occurring at too young an age to be considered natural, although premature, menopause. Not only will these young women potentially lose their reproductive capabilities, but they also are at greater risk for heart disease and osteoporosis. A variety of medical conditions can cause POF, but doctors can not always identify one.