Here's why:

* Gametes are sex cells (sperm in males and eggs in females).

* Testes are the primary male reproductive organs. They are responsible for producing sperm and the male sex hormone testosterone.

While other organs like the epididymis, vas deferens, and prostate are important for the male reproductive system, they do not produce gametes. Their roles are:

* Epididymis: Stores and matures sperm.

* Vas deferens: Transports sperm from the epididymis to the ejaculatory ducts.

* Prostate: Produces fluid that helps to nourish and protect sperm.