There are two locations, which could be used for the retransplantation of the cryopreserved tissue: the remaining ovary and the pelvic wall. Both, the ovary and the subperitoneal pocket in the pelvic wall present a location, where the maturation of follicles is possible. The remaining question is: where do more follicles grow? To answer this question, a study will be necessary. The purpose of this study is to determine whether the pelvic wall or the ovary represents a better location for the maturation of follicles in the context of ovarian transplantation after cryopreservation of ovarian tissue before cytotoxic therapies.