The Danish TURNER Cryopreservation Study

The goal of this clinical trial is to investigate if cryopreservation of ovarian tissue in girls with Turner syndrome can improve their fertility and lead to increased number of liveborn babies of Turner syndrome mothers. Women with Turner syndrome suffer from premature ovarian insufficiency which leads to infertility and lack of estrogen. The main questions it aims to answer are: * Does the number of pregnancies and liveborn children increase after cryopreservation of ovarian tissue in turner syndrome? * Is the possible to predict when a girl with Turner syndrome reach menopause using monitoring of sex hormones? * Is it possible to identify any genes causing ovarian failure in Turner syndrome females? Participants between 2-18 years old will be asked to participate in a laparoscopic surgery and removal of one ovary in order to cryopreserve the tissue until adulthood. The the cortical tissue will be autotransplanted in order to preserve fertility. The participant will during the study period be monitored using sex hormones. Furthermore, the investigators wish to investigate the ovarian tissue using RNA sequencing and DNA methylation analysis. No comparison group is present.