What a varicocele is

A varicocele is a group of swollen veins in the bag of skin that holds the testicles. Tiny valves in the veins stop working properly, so blood does not flow the right way. The blood pools and warms the testicle a little. This can cause aching, can lower sperm quality, and over many years can make the testicle smaller. About 1 in 7 men have one. Many men have no symptoms at all.