The Tanner scale for the maturity of male genitals assigns a maturity stage to the calculated volume ranging from stage I a volume greater than 20 ml .
I am a volume of less than 1.5 ml ; to stage V .
The Tanner scale for the maturity of male genitals assigns a maturity stage to the calculated volume ranging from stage I , a volume of less than 1.5 ml ; to stage V , a volume greater than 20 ml .