Double-blind cross over treatment with mesterolone and placebo of subfertile oligozoospermic men value of testicular biopsy.

Fifty-nine carefully selected oligozoospermic men were randomly treated with mesterolone (75 mg/day) or placebo to improve fertility. After 6 months the medication was changed from mesterolone to placebo or vice versa. Fourteen pregnancies occurred, 7 under mesterolone and 7 under placebo. A testicular biopsy score was of prognostic value: the men who impregnated their partner had a significantly higher mean score than the men who did not fertilize. No other significant differences between these two groups of men were observed. Mesterolone had no significant influence other than placebo.