Incompetent or inadequate valves within the veins along the spermatic cord cause a varicocele. The abnormal valves obstruct normal blood flow causing a backup of blood, resulting in enlargement of the veins. Varicoceles usually develop slowly and usually have no symptoms. Varicoceles are a cause of infertility in men.
Review Date 7/26/2021
Updated by: Kelly L. Stratton, MD, FACS, Associate Professor, Department of Urology, University of Oklahoma Health Sciences Center, Oklahoma City, OK. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.