Ovulatory dysfunction:• PCOS women with amenorrhoea have similar BMD (independent of BMI) to healthy controls (unlike women with HA where BMD is reduced) (18), suggesting that the deleterious effect on bone of amenorrhoea is balanced by other PCOS-related factors (e.g., androgens, insulin, and obesity).Polycystic ovarian morphology:• Not known to have direct effects on bone.Absence of hyperandrogenism:• BMD significantly lower in PCOS women without hyperandrogenism than PCOS women with hyperandrogenism (14). This evidence concerns the gene INS and polycystic ovary syndrome.