If FSH > 30 mIU / ml then 3.33% of hypospermatogenesis, 10.00% of maturation arrest, 36.67% of the Sertoli-cell-only syndrome, 50.00% of seminiferous tubular sclerosis. Agreeing with Islam, we found that FSH level could not replace testicular biopsy, because even with high FSH level, spermatogenesis did exist, and vice versa normal FSH value might be found when failed spermatogenesis such as the Sertoli-cell-only syndrome. Conclusions: Serum FSH can be a predictive index of spermatogenesis.