Since the biogenesis and function of piRNA is tightly associated with that of the PIWI protein subfamily, and MitoPLD is essential for the creation of the 5’ ends of primary piRNAs, the marked reduction of mature piRNAs in sperm of asthenozoospermia patients suggested the dysfunction or loss of expression of these essential enzymes in sperms. This evidence concerns the gene PIWIL1 and Reduced sperm motility.