The dysregulation of sperm functions such as capacitation, hyperactivation, zona pellucida binding, and fertilization-related activities is more pronounced in bilateral varicocele cases due to the differential expression of proteins like glutathione S-transferase Mu 3 (GSTM3), sperm protein associated with the nucleus on the X chromosome B/F (SPANXB/F), cytochrome b5 reductase 2 (CYB5R2), CLGN, and Parkinsonism-associated deglycase (PARK7/DJ-1) [42]. Here, CYB5R2 is linked to varicocele.