['There is evidence that varicocele damage, as reflected by loss of testicular mass, is most striking in the pubertal age group. We attempted to evaluate the long-term effect of early varicocele treatment on testicular growth and sperm count and, thus, determine its prophylactic value.', 'We compared testicular mass and sperm count in 32 men (mean age 28 years) who underwent surgery for varicocele at 11 to 15 years old (mean age 13) to those in 26 untreated, age matched men (mean age 30 years) with varicocele and 27 male controls (mean age 25 years). Mean followup in the treated group was 14.5 years (range 12 to 20). Testicular volumes were measured by ultrasonography.', 'There was no significant difference between left and right testicular volumes in the treated or control group, in contrast to the untreated group, in which the left testicles were significantly smaller. Comparison of testicular mass showed a striking similarity between the treated and control groups, while there was a significant difference when the untreated group was compared to the control and operated groups. Total sperm counts were significantly less in the untreated than the treated and control groups.'] Does varicocele treatment in pubertal boys prevent testicular growth arrest?