Varicoceles are an important, but often unrecognized cause of chronic groin or scrotal pain. Varicoceles are also associated with infertility. To explain varicoceles, it helps to understand the purpose of veins in the body. Veins help return blood to the heart by preventing backward flow of blood. When valves don’t work or deeper veins are obstructed, blood pools in the congested scrotal veins, resulting in vein distension and increased pressure in the scrotum. Varicoceles are also a common cause of low sperm production and decreased sperm quality, which can cause infertility.