Gonadal Tissue Freezing for Fertility Preservation in Individuals at Risk for Ovarian Dysfunction, Premature Ovarian Insufficiency and Clinically Indicated Gonadectomy

* INCLUSION CRITERIA: In order to be eligible to participate in this study, an individual must meet all of the following criteria: 1. Individuals with Turner Syndrome prior to menarche aged 2 years to 12 years whose families seek to store ovarian tissue for possible future use. Or Individuals with galactosemia (age 2-21) Or 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 within 2 years of presentation. Diagnosis of POI is based on 2 elevated FSH concentrations obtained over 1 month apart. Or Children or adolescents aged 2-24 years old who have diminished ovarian reserve based on laboratory findings or who respond poorly to ovarian stimulation for egg freezing. Or Individuals with variations in sex characteristics (or differences in sex development, DSD) including Turner syndrome with Y chromosome material who undergo prophylactic gonadectomy for clinical indications. Or Individuals (2-35 years) receiving high-risk gonadotoxic therapy at the NIH Clinical Center who are at high risk for developing premature ovarian insufficiency and infertility. 2. Stated willingness to comply with all study procedures and availability for the duration of the study. 3. 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: 1. Individuals older than 7 years with psychological, psychiatric, or other conditions which prevent giving fully informed consent or assent. 2. Individuals 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. 3. Individuals whose underlying medical condition significantly increases their risk of complications from anesthesia and surgery. 4. Females with POI due to chemotherapy or radiation treatment 5. Pregnancy or lactation 6. Individuals with VSC who choose to retain gonads after clinical consulting. 7. Individuals with Turner Syndrome who have an undetectable AMH based on testing laboratory reference range.