Antisperm antibodies occur when the body becomes sensitized to sperm. This causes an immune system response that destroys the sperm. There are two main types of anti-sperm antibodies that can prevent sperm cells from doing their job they are anti-sperm agglutinating antibodies, and anti-sperm immobilizing Antibodies. When a couple has difficulty getting pregnant due to anti-sperm antibodies, it is known as immunologic infertility. An anti-sperm antibody test looks for special proteins (antibodies) that fight against a man's sperm in blood, vaginal fluids, or semen. The higher the level of antibody-affected sperm found in the semen, the lower the chance of the sperm fertilizing an egg.