Testes/Testicles

The testes (or testicles) are two olive-sized oval bodies, one on the right side and one on the left side. The testes have two main functions: to produce sperm (the male sex cell) and to produce testosterone (the male sex hormone). The epididymides and the vasa deferentia are attached to the testicles and are important in transporting sperm cells after they develop in the testes.

The term testicles includes the testes as well as the surrounding structures, such as the vas deferens and the epididymis. These two names, testes and testicles, are often used interchangeably even though their definitions are slightly different.