Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Testicular Cancer ?
    ### Response:
    Testicles, or testes, make male hormones and sperm. They are two egg-shaped organs inside the scrotum, the loose sac of skin behind the penis. You can get cancer in one or both testicles.    Testicular cancer mainly affects young men between the ages of 20 and 39.
    