What is the primary function of testosterone in males?

The primary function of testosterone in males centers around the development of male reproductive tissues and secondary sexual characteristics. Testosterone is critical for the proper formation and maturation of male reproductive organs, such as the testes and prostate, as well as influencing the development of secondary sexual characteristics that emerge during puberty, like the growth of facial and body hair, deepening of the voice, and increased muscle mass.

While there are additional roles that testosterone plays, such as its involvement in muscle growth, mood regulation, and fat metabolism, these functions follow from the compound's primary role in sexual differentiation and development. Thus, the focus on testosterone's essential contributions to the reproductive system and its significance in the emergence of male phenotypic traits highlights why this function is considered primary in the context of male physiology.