Prepubertal boys treated for cancer may exhibit impaired fertility in later life. A number of chemotherapeu tic agents have been identified as being gonadotoxic, and certain treatment regimens, such as that used for Hodgkin’s disease, are particularly associated with subsequent infertility. Radiotherapy may also cause gonadal damage, most notably following direct testicular irradiation or total body irradiation. Because of the varied nature of the cytotoxic insult, it can be difficult to predict the likelihood of infertility in later life. Currently it is not possible to detect gonadal damage early due to the lack of a sensitive marker of gonadal function in the prepubertal age group.Semen cryopreservation is currently the only method of preserving fertility in patients receiving gonadotoxic therapy. This is only applicable to postpubertal patients and can be problematic in the adolescent age group. At present there is no provision for the prepubertal boy, although there are a number of experimental meth Prepubertal boys treated for cancer may exhibit impaired fertility in later life. A number of chemotherapeu tic agents have been identified as being gonadotoxic, and certain treatment regimens, such as that that used for Hodgkin’s disease, are particularly associated with subsequent infertility. Radiotherapy may also cause gonadal damage, most notably following direct testicular irradiation or total body irradiation. Because of the varied nature of the cytotoxic insult, it can be difficult to predict the likelihood of infertility in later life. Currently it is not possible to detect gonadal damage early due to the lack of a sensitive marker of gonadal function in the prepubertal age group. Semen cryopreservation is currently the only method of preserving fertility in patients receiving gonadotoxic therapy. This is only applicable to postpubertal patients and can be problematic in the adolescent age group. At present there is no provision for the prepubertal boy, although there are a number o f experimental meth