LH hypersecretion in ~75% of women with PCOS (154) further stimulates theca cell hyperandrogenism, whereas relatively diminished follicle-stimulating hormone (FSH) levels inhibit expansion of follicular size and maturity, curtailing selection of a dominant, pre-ovulatory follicle and diminishing the likelihood of ovulation, as mechanistically illustrated in Figs. 1 and Figs. 2a and 2b. This evidence concerns the gene PLOD1 and polycystic ovary syndrome.