 And the Mishnah deduced that a boy became liable to being considered "a stubborn and rebellious son" from the time that he grew two genital pubic hairs until his pubic hair grew around his genitalia.Rav Judah taught in Rav's name that implied that the son had to be nearly a man.The Mishnah interpreted the words of to exclude from designation as a "stubborn and rebellious son" a boy who had a parent with any of a number of physical characteristics.