Antisperm antibodies (anti-spermatozoa antibodies, sperm antibodies) in the form of autoantibodies in male and alloantibodies in female patients directed against sperm antigens may prevent fertilization of the oocyte into the female genital tract and are therefore one of the major reasons for an immunologically induced infertility. Once sperm and blood come in contact, whether in the male or female, specific antibodies are produced against them by specialized blood cells called T- and B-lymphocytes. The three main types of sperm antibodies produced are Immunoglobulin G (IgG), Immunoglobulin A (IgA) and Immunoglobulin M (IgM). These antibodies bind to the proteins (antigens) on the sperm head, midpiece or tail.