Both immunocytochemical method and cell-impermeable fluorescei-tagged progesterone coupled to BSA complex (P-FITC-BSA) showed that expression of PGR in men with oligozoospermia, asthenozoospermia, and oligoasthenozoospermia was significantly lower than that of men with normal spermatozoa, indicating that PGR might be a potential marker for sperm function (19). Here, PGR is linked to Reduced sperm motility.