Which hormone is considered the main sex hormone in male mammals?

Testosterone is recognized as the primary sex hormone in male mammals due to its crucial role in the development and regulation of male reproductive tissues and secondary sex characteristics. This hormone is primarily produced in the testes and is responsible for the growth of male genitalia during embryonic development, as well as for the onset of puberty and the development of features such as increased muscle mass, body hair, and a deeper voice.

In addition to its effects on physical traits, testosterone also influences libido, sperm production, and overall reproductive function. It plays a vital role in maintaining male health throughout life, impacting various bodily functions beyond reproduction, including bone density and fat distribution. Understanding testosterone's functions helps clarify its significance compared to other hormones, which serve different roles in both males and females. For instance, estrogen and progesterone primarily regulate female reproductive functions, while cortisol is involved in stress responses.