Published online by Cambridge University Press: 05 April 2021
The year 2020 is the fortieth anniversary of the introduction of the concept of “sperm DNA fragmentation” as related to human and animal male factor fertility. This concept was introduced by Donald Evenson in a Science article (1980) that also introduced the first test for its detection, the Sperm Chromatin Structure Assay (SCSA®). Sperm DNA fragmentation is defined as sperm single and double DNA strand breaks. Experiments on bulls, boars and stallions clearly show that the SCSA test identifies the highest fertile animals. Thousands of measurements on clinical human semen samples also clearly show that when more than 25 percent of sperm (DFI pecentage) in an ejaculate have measurable DNA fragmentation the probability of live birth pregnancy is significantly diminished. SCSA data on percentage DFI and Mean DFI are the same, meaning that the SCSA test measures the total of sperm DNA strand breaks detected with acridine orange staining.