Table 1. Prevalence of testicular histological findings according to the Copenhagen criteria.

Index	Absolute frequency			Relative frequency (%)		Absolute difference (%)	P value
	Right	Left		Right	Left
1.1.1.0	8	8		40.0	40.0	0.0	1.0000
1.2.2.0	5	4		25.0	20.0	5.0	0.7044
1.3.3.0	1	2		5.0	10.0	5.0	0.5465
1.5.5.0	1	1		5.0	5.0	0.0	1.0000
1.6.3.0	4	4		20.0	20.0	0.0	1.0000
1.7.2.0	1	1		5.0	5.0	0.0	1.0000
Total	20	20		100.0	100.0

To compare the frequencies for each index, we used the Z-statistic for independent proportions (Pearson). No significant differences were noted (P<0.05). 1.1.1.0, adult testis with homogeneous aspect, normal spermatogenesis, and no abnormalities. 1.2.2.0, adult testis with homogeneous aspect, reduced number of spermatids, and no abnormalities. 1.3.3.0, adult testis with homogeneous aspect, maturation arrest at the primary spermatocyte stage, and no abnormalities. 1.5.5.0, adult testis with homogeneous aspect and characteristics indicative of Sertoli-cell-only syndrome. 1.6.3.0, adult testis with heterogeneous aspect and normal spermatogenesis or reduced number of spermatids. 1.7.2.0, adult testis with heterogeneous aspect and germ cell arrest at primary spermatocyte stage.