Cancer treatment can affect the testicular function, including sperm and hormonal functions. The aim of this study is to assess the testicular function and semen quality in young men who recover from childhood and adolescent cancer in Hong Kong. This can provide more information for pre-treatment counselling as well as improve post treatment survivorship care. The testicular function will be compared to aged-matched controls from men attending the Family Planning Association for premarital check-up.

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.

Inclusion Criteria:

• Men who have received chemotherapy and/ or radiotherapy for cancer diagnosed when they were < 18 years old.
• > 18 years old to 50 years old
• Cancer in remission for at least 2 years

Exclusion Criteria:

• Unable to ejaculate by masturbation to provide semen samples
• Cryptorchidism, testicular cancer, history of vasectomy
• On testosterone replacement therapy
• Refusal to join the study

Target participant Population

• 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.
• Aged-matched controls from men attending the Family Planning Association for premarital check-up