Q: What is a varicocele?

A: A varicocele consists of abnormally distended veins, blood vessels which contain venous blood. Varicoceles resemble varicose veins in the legs, distended blood vessels in the legs, except in this case the veins lead away from the testicles. Veins generally allow only a "one-way street" flow, allowing the blood to drain from the testicle, but not to return. When there is a varicocele, the blood instead of moving constantly away from the testicle returns to the testicle, causing a change in blood flow of the testicle, increasing the testicle's temperature and thus changing the sperm production.