IVimOva project aims to offer a realistic fertility prevention therapy for trans men (male -> male transgender patients). One aspect of transgender care, means that offered both hormone therapy and surgery for transgender people. The ovaries are removed at the same time in the transition of surgery trans men. This surgery makes these people are infertile. If fertility protective technique, the outer parts of the ovary consisting of the cortex are herein frozen primordial follicles. However, the clinical applicability of this technique is for fertility protective trans men nil, since such persons do not transplantation of this tissue will carry out because of the fact that there will be produced again female hormones in the body.