The Prostate Bladder is a gland that only men have. It is about the size of a walnut and sits below the neck of the bladder, surrounding the bladder outlet (the urethra). The prostate makes a milky fluid, which is part of semen and feeds the sperm. The prostate is just in front of the rectum. The urethra runs through the center of the prostate, from the bladder to the p*nis, letting urine flow out of the body. Prostate cancer is the most common form of cancer in men (besides skin cancer), but only one in 41 men die from prostate cancer. prostate and bladder