RPS4Y2 and Azoospermia: The major Y-chromosome proteins include the testis-specific human protein RBMY, a probable human spermatogenesis factor protein, RPS4Y2, PRY2, XKRY2, VCY1B, VCY, UTY, USP9Y, testis-specific transcript, Y-linked 9A (TTTY9A), TMSB4Y, DDX3Y, deleted in azoospermia 1, deleted in azoospermia 3, deleted in azoospermia 2, deleted in azoospermia 4, chromodomain protein, Y-linked, 2A (CDY2A), chromodomain protein, Y-linked, 2B (CDY2B), B, CDY1B, CDY1, BPY2C, BPY2, ASSP6, EIF1A, JARID1D, heat shock transcription factor, Y linked 2 (HSFY2) and GOLGA2LY1.