Heterologous ovum penetration test and seminal parameters in fertile and infertile men.

Sperm penetration rates in the heterologous ovum penetration test were correlated with results of routine semen analysis in 30 fertile and 50 infertile men. There was no difference in penetration rates when comparing infertile men with normal and abnormal seminal parameters, nor was any difference seen between fertile (15-83%) and infertile men (8-83%). Of the 22 infertile men with normal seminal characteristics, seven had partners with no discernible reproductive dysfunction. The penetration rates of these men (38-81%) did not differ from those of fertile men. Stepwise regression analysis of seminal characteristics, with penetration as the dependent variable, indicated that sperm count and morphology are the most important seminal parameters for fertility assessment. Discrimination analysis revealed that sperm numbers and morphologic variables provide significant information for discriminating between fertile men and infertile men with normal or abnormal seminal characteristics. Sperm penetration and motility were not indicated as important factors. The present data suggest that, in unselected male patients seeking reproductive evaluation, the sperm penetration assay did not yield any additional information on the cause of infertility.