The gamete-producing organs of the male reproductive system are the testes (singular: testis). The testes are a pair of oval-shaped glands located in the scrotum, which is a sac of skin and muscle that hangs outside the body cavity. The testes are responsible for producing and storing sperm, which are the male gametes.
The testes are composed of seminiferous tubules, which are coiled structures where sperm cells are produced through a process called spermatogenesis. The sperm cells then move into a network of ducts within the testes, where they mature and are stored until they are released during ejaculation.
In addition to producing sperm, the testes are also responsible for producing and secreting male sex hormones, such as testosterone. These hormones play a key role in the development and maintenance of male reproductive organs and secondary sexual characteristics, such as facial hair, deep voice, and muscle mass.