The prostate is a walnut-sized gland that forms part of the male reproductive system. The gland has two lobes, enclosed by an outer layer of tissue. It is positioned in front of the rectum and just below the bladder, where urine is stored. The prostate also surrounds the urethra, the canal through which urine passes out of the body. It is common for the prostate gland to become enlarged as a man ages, causing a condition known as benign prostatic hyperplasia (BPH). More than half of men 50 and older, and 90 percent of those 80 and older, have BPH. The condition can squeeze the urethra, making it harder for the bladder to empty and causing urinary symptoms such as urgency, leaking, dribbling and more frequent urination.