AR and Menstrual disorder: The AR, located on the X-chromosome at Xq11–12, presents a genetic polymorphism in exon 1, defined by a poly-glutamine (CAG) repeat region (8–35 repeats in most cases) [49]: a shorter length of this region has been typically associated with an increased androgen sensitivity; for this reason, CAG repeat polymorphism in the AR gene has been linked to PCOS amplifying women’s response to male hormones and leading to virilization and menstrual disorders [50].