Reduced fertilization ability of zona-free hamster ova by spermatozoa from male partners of normal infertile couples.

Zona-free hamster ova were used as a penetration test system for human semen obtained from male members of infertile couples. Forty semen samples from normal infertile couples were tested and compared with penetration rates obtained with control semen samples from fertile donors. Normal penetration rates ranged between 20-100%. Out of the 40 tested males, 11 were found to have penetration rates below 10%, two had between 11 and 19%, and in the remaining 27, the rate was above 20%. Three women, whose husbands were found to be in the first group (penetration rate below 10%), conceived after artificial donor insemination within three months of treatment. Thus, the use of the human-hamster ova penetration test should be used as an additional tool in diagnosis of infertility.