INCLUSION CRITERIA:  In order to be eligible to participate in this study, an individual must meet all of the following criteria:  Prepubertal females with Turner Syndrome and galactosemia aged 4 years to 12 years who have not yet demonstrated signs of puberty whose families seek to store ovarian tissue for possible future use. Adolescent females up to age 21 years old, who have undergone menarche and are subsequently diagnosed with premature ovarian insufficiency and their last menstrual period occurred w ithin 2 years of presentation. Diagnosis of POI is based on 2 elevated FSH concentrations obtained over 1 month apart. Stated willingness to comply with all study procedures and availability for the duration of the study. Ability of subject, parents or guardian to understand and the willingness to sign a written informed consent document.  EXCLUSION CRITERIA:  An individual who meets any of the following criteria will be excluded from participation in this study:  Females older than 7 years with psychological, psychiatric, or other conditions which prevent giving fully informed consent or assent. Females with a pelvic mass tumor noted on pre-operative ultrasound, will undergo usual care for the underlying condition and will not undergo oophorectomy for ovarian tissue cryopreservation Females whose underlying medical condition significantly increases their risk of complications from anesthesia and surgery. Females with POI due to chemotherapy or radiation treatment Pregnancy or lactation