Given the data described herein, there is reason for even greater optimism about the possibility of fertility among patients with testicular cancer. Fertility issues have been and will continue to be important as different therapies for nonseminomatous cancer are proposed. For example, we previously calculated that the difference in fertility between patients who are treated with expectant therapy versus lymph-adenectomy for clinical stage I disease was only 16 patients in favor of expectant therapy. If new data on relapse rates after expectant therapy (e.g., 30 per cent) and better ejaculation preservation rates after lymphadenectomy (e.g., 85 per cent) are incorporated into this calculation, the number benefited falls to 6 patients. It has also been proposed that patients with low-volume stage IIB disease should receive initial chemotherapy and that lymphadenectomy should be reserved for those patients with residual disease. Applying these calculations along with certain additional assumptions, the difference in fertility between these two treatment alternatives is only 4 patients in favor of initial chemotherapy (P.H. Lange; manuscript in preparation). However, this approach has significantly greater toxicity. Much more must be done to improve our understanding and management of infertility in patients with testicular cancer. Additional tasks include the need to establish the exact ratio of patients with testicular cancer who have infertility that precedes or is a result of their disease, and to develop methods for predicting fertility status so that treatment can be tailored accordingly. Also, we must consolidate and improve the indications, techniques, and results for fertility-sparing lymphadenectomy in ways that have been described herein. In addition, the exact damage-to-benefit ratio for the number of courses and types of chemotherapy administered to patients will need to be studied carefully and prospectively, preferably in cooperative groups. The accelerating advances in in vitro fertilization and cryopreservation must be watched carefully, and their application to appropriate patients with nonseminomatous cancer should be encouraged. Cryopreservation before therapy should continue to be advocated. All of these tasks are extremely difficult because they require precise analysis of carefully generated statistics and difficult judgments about individual human values.