The “mix” of the term and the preterm group, implies a higher prevalence of PCOS than in the background population, as we did not include all term births in the period when we assembled the patients with preterm birth, but is an advantage in the current study, as this increased the power without increasing the study to compare the AMH/AFC-ratio in women with PCOS, to those without. The gene discussed is AMH; the disease is polycystic ovary syndrome.