The scrotum holds the testicles and also contains the veins and arteries that deliver blood to the reproductive glands. Varicocele is a collection of enlarged veins within the scrotum due to a vein abnormality. It is similar to varicose veins which can occur in the legs. Varicocele can cause reproductive issues if the valves within the testes cause blood to pool within the scrotum, as it decreases sperm production. The pooling of blood affects the circulation and temperature of the testes, causing decreased sperm motility and poor morphology.