Hi, A varicocele is an enlargement of the veins within the scrotum. A varicocele is similar to a varicose vein that can occur in your leg. Due to failure of valves inside the testicular veins. Not due to gyming. Varicoceles are a common cause of low sperm production and decreased sperm quality, which can cause infertility. However, not all varicoceles affect sperm production. Varicoceles can also cause testicles to fail to develop normally or shrink. Most varicoceles develop over time. Fortunately, many varicoceles don't need treatment. If a varicocele causes symptoms like pain and severe enlargement, it often can be repaired surgically.