A specific haplotype (AGATA) in the estrogen receptor alpha (ER1) gene was recently described as a new risk factor for cryptorchidism in the Japanese population. In this ethnic group, single-nucleotide polymorphism 12 (SNP12) was concluded to be the tag SNP for the AGATA haplotype.A large group of patients (total number=335) and controls (total number=567) of two Caucasian populations were analysed for the AGATA haplotype and SNP12 to verify whether this genetic variant and its tag SNP were associated with cryptorchidism or with severe spermatogenic failure.We confirm that SNP12 is the tag SNP for the AGATA haplotype also in Caucasians. However, in contrast with the Japanese population we found a protective effect for ESR1 SNP12 on cryptorchidism in the Italian population. No association between SNP12 and severe spermatogenic disturbances was observed.The observed associations (although with opposite effect) with cryptorchidism encourage future studies on independent cases and controls from different ethnic and geographic origins. On the other hand, in contrast with other ESR1 polymorphisms, SNP12 polymorphism is not associated with severe male factor infertility in two independent European population.