It surrounds the first part of the tube (urethra) which carries urine from the bladder to the penis.

The prostate produces a thick white fluid called semen which mixes with the sperm produced by the testes. It also produces a protein called prostate specific antigen (PSA) which turns the semen into liquid.

The growth of prostate cells and the way the prostate gland works is dependent on the male sex hormone, testosterone, which is produced in the testicles.