The sign of having reached the age of legal responsibility (bulūgh) for a girl is the completion of nine lunar years. For boys, it is one of three things: 1. growth of thick hair below the navel and above the genitalia, [and on the face and above the lips (see next ruling)]; 2. ejaculation of semen; 3. completion of fifteen lunar years. Ruling 2271.* The growth of thick hair on the face and above the lips are signs of bulūgh.
However, the growth of hair on the chest and under the armpits, and the deepening of a boy’s voice and suchlike, are not signs of bulūgh.