Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Prostate Enlargement: Benign Prostatic Hyperplasia ?
    ### Response:
    The cause of benign prostatic hyperplasia is not well understood; however, it occurs mainly in older men. Benign prostatic hyperplasia does not develop in men whose testicles were removed before puberty. For this reason, some researchers believe factors related to aging and the testicles may cause benign prostatic hyperplasia.
    