RESUMEN
We have operated on 2204 cryptorchid testis between 1972 and 1995. We took pathological specimens, not only in the undescended testis but also in the normally descended contralateral testis in 122 children. Clinical, surgical and anatomopathological records were reviewed. Moreover, we have studied the spermiograms in 10 young men. We found the Tubular Fertility Index (TFI) was abnormal in 37% of the contralateral testis. In 5 cases we didn't find germinal line. The Tubular Diameter was abnormal in 6.5% of the contralateral testicles only. When we compared the anatomopathological records in the contralateral testis depending on the surgical age and the surgical location of the undescended testis, we didn't find significant differences. When we studied the spermiograms in the 10 young men we obtained some cases where the TFI and the spermiogram were discordant. In conclusion, more than 1/3 of the children with unilateral undescended testis have an abnormal TFI in both testis. Moreover, neither the surgical age nor surgical location of the undescended testis have an influence on the contralateral TFI. Finally, according to the spermiogram results we should question TFI as a fertility index.