The etiology of altered spermatogenesis is  unknown in about 40% of cases and a large proportion of it is likely related to still unknown genetic factors. The identification of  the “missing” genetic causes is of importance both for genetic counseling and for the development  of  future etiologic therapies. Our study, by screening over 1200 subjects (infertile versus normozoospermic men) provided the first evidence for three X chromosome-linked recurrent deletions associated to spermatogenic impairment. One of them, CNV67, is likely to affect two genes with testis specific expression (MAGEA9 and HSFX1/2) and it was absent in normozoospermic controls. Due to its relatively high frequency in oligo/azoospermic men (1.1% ) the deletion has potential clinical and basic research  implications. (By Professor Csilla Krausz, http://jmg.bmj.com/content/early/2014/01/13/jmedgenet-2013-101988 )