Ovarian Stem Cells From Women With Ovarian Insufficiency

Background: \- Primary ovarian insufficiency (POI) is a condition that affects ovary function. It means that the ovaries are not able to function at a level appropriate for a woman's age. Previously, it was thought that women had only a fixed number of eggs that were lost each month until none were left at menopause. However, recently, stem cells have been found in the ovaries of adult women. These stem cells may be able to make new eggs. Studying these cells may help women with POI in the future. Researchers want to collect ovarian tissue from women with POI to investigate ovarian stem cells. Objectives: \- To collect ovarian tissue from women with primary ovarian insufficiency. Eligibility: \- Women between 18 and 50 years of age with primary ovarian insufficiency. Design: * Participants will be screened with a physical exam and medical history. They will also have a full gynecological exam. They will provide blood and urine samples. * Participants will donate ovarian tissue for study. It will be collected through outpatient surgery. The surgery will take either half of an ovary or a full ovary. * Treatment will not be provided as part of this study.