Beyond the applications for assisted reproduction technologies, the phenotype described in Epas1-cKO females in this study also highlights the need for consideration when administering EPAS1 inhibitors (e.g. Belzutifan) for the treatment of rare diseases (such as polycythemia and paraganglioma), and von Hippel–Lindau (VHL) associated tumours57. Here, VHL is linked to polycythemia.