What is testosterone primarily responsible for in males during puberty?

Testosterone plays a crucial role in the development of male characteristics and the maturation of male sexual organs during puberty. This hormone, produced primarily in the testes, leads to physical changes such as the growth of the penis and scrotum, the deepening of the voice, the growth of facial and body hair, and increased muscle mass. It is instrumental in the development of secondary sexual characteristics that distinguish males from females.

While testosterone can influence mood and has some metabolic regulatory functions, its primary role during puberty is the stimulation of the growth of male sex organs and the promotion of male secondary sexual characteristics. This makes the chosen answer particularly relevant to the physiological changes taking place in boys as they transition into adulthood.