Published online by Cambridge University Press: 01 February 2010
The semen analysis (SA) in the form in which it appears today is a relatively recent invention. The definition of a “normal” semen analysis was not standardized until publication of the World Health Organization (WHO) Laboratory Manual for the Examination of Human Semen and Sperm–Cervical Mucus Interactions in 1980. Between 1869, when Sims reported that sperm needed to be present in cervical mucus for conception to occur, and 1951, the Sims–Huhner postcoital test and the presence of motile sperm on a microscopic slide were considered the only tests necessary to evaluate male fertility. The postcoital test was used as part of their initial evaluation of infertile couples by 92% of infertility specialists in private practice in the United States according to a survey taken in 1998. Examination of a droplet of ejaculate under the microscope remains a highly accurate, easy-to-perform “qualitative” test of male fertility.
In 1951, MacLeod and Gold analyzed the sperm counts of 1,000 fertile and 1,000 infertile men stratified at intervals of 20 × 106/mL. They observed that 19% of infertile men had counts of less than 20 × 106/mL, compared to 8% of fertile men. On this basis they stated that men with sperm counts above 20 × 106/mL were fertile, and men with counts below that concentration were subfertile, even though they had not further stratified counts of less than 20 × 106.