This chapter introduces medical students, residents, fellows, and practicing urologists to surgical syndromes that can affect a man's reproductive potential. The most widely accepted theory of how varicocele affects testicular function is that of elevated testicular temperature. When obstructive azoospermia is present, sperm production by the testis remains normal and often epididymal tubules become quite dilated. The yield of sperm from the epididymis is logarithmically higher than the yield of sperm from the testis. The anatomy of the male reproductive tract is such that sperm exit the testes, travel through the epididymis, and enter the vas deferens. The vas deferens travels into the inguinal canal with the spermatic cord and then dives posteromedially to fuse with the seminal vesicles at the ampulla of the vas deferens. Any serious medical illness or surgery can result in impaired testicular function and disruption of normal ejaculatory function.