Ovarian Tissue Cryopreservation for Fertility Preservation in Girls and Women

The primary objective of this study is to determine the efficacy of ovarian tissue cryopreservation using slow-freeze and vitrification methods in enabling long-term preservation of ovarian function and fertility, in females undergoing treatment that may cause infertility. This study will provide study participants with their own tissue to cryopreserve and reserve for future use and: * Determine the efficacy of ovarian cryopreservation techniques. * Provide long-term follow up for patients who have undergone ovarian tissue cryopreservation for participants' own use. In addition to providing study participants with the future opportunity to use their tissue with the intent to reinstate ovarian function, this study will provide research tissue to the embryology research lab at the Family Fertility Center at Texas Children's Hospital that will be used to: * Optimize techniques for ovarian tissue cryopreservation of ovarian tissue for use in future retransplantation). * Investigate factors affecting successful maturation and quality of immature oocytes obtained from ovarian tissue including growth factors, hormones and other culture conditions.