Making Epididymal Sperm Counts (Yefan Wang, TherImmune Research Corporation, Gaithersberg, Maryland). Epididymal sperm counts are a widely used, simple and sensitive method of assessing the effects of male reproductive toxicants on the epididymal and/or testicular site of action. After careful dissection of the tissues and further processing, the sperm suspensions are counted using a hemacytometer and analyzed for effect.