Females' isoimmunity to sperm is associated with sperm autoimmunity in their husbands.

One hundred twenty-five fertile couples and 334 infertile couples were tested for the presence of cytotoxic and hemagglutinating antibodies to sperm. Elevated titers of sperm antibodies were absent in both partners of fertile couples. Of 79 infertile males with levels of sperm antibodies in the previously established negative range, 97% had wives who also had low titers of sperm antibodies. Of 255 infertile males positive for serum hemagglutinating antibodies, 56% had wives whose serum contained significant circulating hemagglutinating antibodies, while 93 of 202 (46%) males with significant cytotoxic antibody titers had wives whose serum contained elevated cytotoxic antibody titers. The females developed elevated titers of sperm antibodies in the serum and cervical mucus if their husbands had significant titers of hemagglutinating and cytotoxic sperm antibodies in the serum and seminal plasma samples. Females' isoimmunity to sperm was significantly associated with their husbands' autoimmunity to sperm and infertility.