Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Prostate Diseases ?
    ### Response:
    The prostate is a gland in men. It helps make semen, the fluid that contains sperm. The prostate surrounds the tube that carries urine away from the bladder and out of the body. A young man's prostate is about the size of a walnut. It slowly grows larger with age.
    