The prostate gland is located behind a man’s pubic bone. It is surrounded by the pelvic muscles. The prostate gland’s main function is to do with reproduction. Sperm is produced by the testicles. The vas deferens then carries the sperm to the prostate gland and the seminal vesicles. There the sperm mixes with fluid from the prostate and seminal vesicles. The ejaculation fluid is comprised of 5% sperm and 95% seminal/prostate fluid. The fluid produced by the prostate is called prostate-specific antigen (PSA). In semen it acts to liquefy the seminal fluid after ejaculation so that sperm can swim freely.