The male reproductive system consists of both external and internal parts. The external parts include the penis, which is used for sexual intercourse, and the scrotum, which contains the testes. The internal parts include the vas deferens, which transports sperm, and the seminal vesicles and prostate gland, which produce fluid that forms semen. Sperm are produced in the seminiferous tubules in the testes and are ejaculated through the urethra during sexual arousal and orgasm.