Bone Marrow Cell Engraftment of the Uterus and Genetic Studies of Reproductive Functioning

Background: \- Some transplant recipients have been found to have cells in their uterus that come from the donor. Researchers want to study uterine tissue from three different groups of women: (1) healthy volunteers, (2) people who have had a stem cell transplant, and (3) people with rare diseases or conditions that affect reproduction. These samples will help researchers learn more about the way stem cells work in the reproductive tract. Objectives: \- To collect cells from the uterus to study how stem cells work in the reproductive tract. Eligibility: \- Women at least 18 years of age. Design: * Participants will be screened with a physical exam and medical history. They will also have blood and urine tests. * Participants will have an endometrial biopsy to collect cells for study. The biopsy visit will take 1 to 2 hours.