Final answer:
Testosterone is a steroid hormone produced by Leydig cells that regulates male sexual development and has various functions in both males and females.
Step-by-step explanation:
Testosterone, an androgen, is a steroid hormone produced by Leydig cells.
In male embryos, testosterone is secreted by Leydig cells by the seventh week of development, with peak concentrations reached in the second trimester.
This early release of testosterone results in the anatomical differentiation of the male sexual organs.
Testosterone plays an important role in muscle development, bone growth, the development of secondary sex characteristics, and maintaining libido in both males and females.