Testicular Function and Semen Quality in Male Childhood and Adolescent Cancer Survivors

This is a cohort observational study. The target population for the trial will be men who have received chemotherapy and/ or radiotherapy for cancer diagnosed when they were \< 18 years old, currently \> 18 years old to 50 years old and cancer in remission for at least 2 years. The testicular function, including sperm and hormonal functions, will be compared with aged-matched controls from men attending the Family Planning Association for premarital check-up.