Final answer:
Testosterone is produced by the testes, a male sex hormone that plays a crucial role in development and secondary sex characteristics.
Step-by-step explanation:
The primary hormone produced by the testes is testosterone, which is a male sex hormone. It plays a crucial role in the development of the reproductive system, maturation of sperm cells, and the development of secondary sex characteristics. Testosterone is not produced by the posterior pituitary, anterior pituitary, or hypothalamus.