Fang et al. disclosed that the levels of growth differentiation factor-8 (GDF-8) in FF at oocyte retrieval were higher in women with PCOS as compared to the FF of women without PCOS, this study also provided evidence that aberrant expression of GDF-8 in the FF of women with PCOS was associated with subnormal progesterone secretion and poor pregnancy outcomes [41]. This evidence concerns the gene MSTN and polycystic ovary syndrome.