Also known as testicles, this is an organ that is responsible for the production of sperm cells in the male reproductive system, as well as androgens (a male hormone). They are two oval shaped organs located directly in between the penis and the anus. The testes move freely in the scrotum and each testis are attached to the body by a thin chord called the spermatic cord. This cord contains the nerves and blood vessels or the testes as well as the vas deferens, which carries the sperm from the testes into the urethra; the urethra is the passageway for sperm to the outside of the body at ejaculation.
The process of making sperm starts in germ cells. As they mature into sperm cells, germ cells move from the lining, through the maze of seminiferous tubules (located inside the testes) and to the epididymis. The epididymis stores sperm cells so they can completely mature. Mature sperm cells travel through the vas deferens. Along the way, fluids made by the seminal vesicles and the prostate gland mix with the sperm cells to create semen. The semen is pushed out of body through the urethra during ejaculation. Sperm in the semen can fertilize a female egg to start a pregnancy.