Approximately 15% of men with newly diagnosed cancer are younger than 55 years, and about 26% of them are younger than 20 years. However the most common cause of fertility disorders is oncological treatment itself, the oncological diseases, changes in anatomy, and primary or secondary hormonal insufficiency are also significant factors. The chemotherapy, radiation, or their combination reduce sperm count, impair sperm motility and cause disorders in morphology and DNA integrity. Prognosis of sperm production recovery depends on the type of cancer, stage of the disease, patient age, drug treatment, treatment route and dosage, and pre-treatment male fertility.