Testicular varicocele is present in 15 % of adolescent boys. The very impact of this pathology and who will be at risk of developing into infertility remains unclear. Research on the pathophysiology, results of surgical or radiological interventions and potential predictors for long-term impairment of spermatogenesis and thus fertility is still ongoing. Indications for treatment are mainly based on differences in testicular volumes as semen parameters are most often not available; however, whether testicular volume is a valuable prognostic parameter for later fertility remains questionable. Approximately 50 % of adolescent patients with varicocele experience spontaneous increase of testicular volume without any intervention.