There has been a significant improvement in survival rates over the last decade as a result of advances in the treatment of cancer in children. One of the consequences of chemotherapy may be damage to the ovarian function, which can lead to loss of fertility. Methods of fertility protection have been developed for adult women as a result of advances in reproductive medicine, which make the option of becoming pregnant after surviving cancer realistic. However, only some of the methods can be used in prepubescent girls and adolescents. In addition, a higher number of miscarriages and premature births have been found in women who underwent pelvic radiotherapy during childhood or adolescence and the children were more commonly growth retarded. The effects of cancer treatment on the ovarian function and later fertility should be discussed at the start of treatment.