which is used to assess the maturity of the male genitalia, assigns a maturity stage to the calculated volume ranging from stage I, a volume of less than 1.5 cm³; to stage V, a volume greater than 20 cm³. Normal volume is 15 to 25 cm³; the average is 18 cm³ per testis (range 12-30 cm³).

The number of spermatozoa an adult human male produces is directly proportional to testicular volume, as larger testicles contain more seminiferous tubules and Sertoli cells