What is the main role of the testes in the male reproductive system?

The main role of the testes in the male reproductive system is the production of sperm. The testes are the male gonads and are responsible for the development and maturation of sperm cells through a process known as spermatogenesis. This process occurs within the seminiferous tubules located inside the testes. In addition to producing sperm, the testes also play a significant role in the production of testosterone, which is crucial for the development of male secondary sexual characteristics and the regulation of various reproductive functions. However, the primary function specifically linked to the testes is sperm production, making this the correct answer.