Tribestan administered to males with idiopathic oligoasthnozoospermia or with spermogram disturbances due to varicocele, has shown increased concentration of spermatozoa, increased percentage of motile spermatozoa. Increased spermatozoa motility rate and, for some cases, increased volume of ejaculate of 1 to 2 ml. In controlled studies the number of Sertoli cells increased by 40% with no change in the number of Leydig cells.