['To determine whether corticosteroid immunosuppression (CS) administered to the male partner together with intrauterine insemination (IUI) is preferable compared to IUI alone in treating male autoimmune subfertility.', 'Thirty-six couples with proven male immunological subfertility were randomly assigned to begin CS + IUI (n = 18) or IUI (n = 18) treatment and progressed alternatively to receiving each treatment modality for three cycles unless pregnancy occurred. Each couple served as their own control. The administered corticosteroid was soluble prednisolone.', 'Five pregnancies were achieved with 77 cycles of CS + IUI and seven pregnancies with IUI alone. The pregnancy rates per cycle were 6.5% with CS + IUI and 9.21% with IUI, while the pregnancy rates per couple were 16.13% with CS + IUI and 21.2% with IUI alone. These rates do not differ to a statistically significant degree (P > 10%).'] Does corticosteroid treatment improve the results of intrauterine insemination in male subfertility caused by antisperm antibodies?