These findings are consistent with recent studies [15, 21] and may explain differences with other studies which reported an association between these markers and endometriosis in follicular fluid using semi-quantitative western blotting, such as Kawabe et al. reporting significant reduction in GDF9 mRNA expression in granulosa cells of women with moderate to severe endometriosis [19, 20]. This evidence concerns the gene GDF9 and endometriosis.