Even though the vagina contains few Bifidobacterium, these bacteria are essential as it was demonstrated to reduce inflammation, and increase immunity and the process of folliculogenesis, and to regulate the levels of the sexual hormones FSH and LH in women with polycystic ovary syndrome (PCOS) [32,33,34], indicating a potential positive impact on oocyte maturation and quality [35]. This evidence concerns the gene BRD2 and polycystic ovary syndrome.