[Bilateral testicular biopsies and histological comparison of both testes].

Both testes from 37 men were biopsied; 17 idiopathic azoospermia and 20 varicocele patients either azoospermic or severely oligozoospermic. Histological findings of both testes were studied by means of Johnsen's score count. In idiopathic azoospermia, there was no difference between bilateral testes. Unilateral biopsy of the testis is indicated in this type of male infertility. In varicocele, the testis on the left side showed more advanced damage of the seminiferous tubuli than the right side on average count. Bilateral testicular biopsy is indicated in varicocele cases.