What most people know about the prostate gland is that it tends to develop infections and cancer in men over the age of sixty-five. But unlike another organ prone to infection called the appendix, the prostate does important work. In fact, the human species couldn’t survive without it. A walnut-sized organ resting under the bladder, the prostate produces a fluid that constitutes most of the liquid in semen. The prostate fluid in semen helps keep sperm healthy and active after ejaculation. Since lively sperm have a better chance at fertilization, a working prostate is crucial for human reproduction.