"Two mosaic-YY males carrying asymmetric Y chromosomes"

Two patients were referred because of oligospermia and azospermia, respectively. Karyotypic analysis revealed two mosaic-YY males carrying asymmetric Y chromosomes. To our knowledge, no instance of double unequal Y chromosomes has been reported so far in human males. Results of fluorescent in situ hybridization (FISH) studies in spermatozoa from one of these patients revealed a significantly high number of hyperaploid spermatozoa