Application of interspecies in vitro fertilization in the initial assessment of the infertile couple.

Methods to evaluate male reproductive potential are limited. Conventional semen analysis does not necessarily reflect sperm functionality. In this study we investigated the correlation of the interspecies penetration test with clinical evaluation of 106 infertile couples. In vitro penetration results in 92 of 106 men correlated well with clinical diagnosis. In 28 couples with a male infertility factor, the mean penetration rate was 18%, whereas in 78 infertile couples with no known male factor, the rate was 50%. The mean for all patients tested was 40%. This was well below a mean of 73% for a donor population. The major discrepancy between the interspecies penetration test and clinical findings occurred in a group of nine patients with 0% penetration who had been judged normal by history and semen analysis. In general, the interspecies penetration test correlates well with male clinical evaluation but does the complementary information in certain cases. At present, its greatest utility seems to be in evaluation of unexplained infertility, in unexplained failure of female therapy, or in selection of patients for donor insemination.