When do male human beings stop growing taller?

In 1955 he took J.D. (Jonathan David Williams), someone who was supposed to be a future whitelighter. When he materialised J.D. in order to vanquish him after his father's death, J.D. escaped. His whitelighter Sam was able to track him down and together with Paige he tries to save his protegé. He was trapped inside his own collage by Paige.