Prostate gland enlargement is less common in Chinese, Indian and Japanese men. However it is so common among Americans and Australian men. Researchers are still puzzled why this is like this. The prostate gland is the male organ that produces most of the fluid in semen, the milky- fluid that nourishes and transports sperm out of the penis during ejaculation (orgasm). It sits beneath your bladder. The tube that transports urine from the bladder out of your penis (urethra) passes through the center of the prostate.
When the prostate enlarges, it begins to block (obstruct) urine flow. According to researchers, most men have continued prostate growth throughout life.
In many men, prostate gland enlargement continued growth enlarges the prostate enough to cause urinary symptoms or to significantly block urine flow.
Doctors, however say they are not sure exactly what causes the prostate to enlarge. It may be due to changes in the balance of sex hormones as men grow older.