Individual characteristics of human spermatozoa

We have investigated the variability of some characteristics of a sperm sample in 18 young volunteers in good health who were examined twice per month over a period of two years, and in about one hundred men undergoing treatment for sterility and for whom more than 4 spermiograms had been established during the past three years. The results of statistical analysis indicate that the most characteristic individual feature is the concentration of spermatozoa.