In addition to the factors mentioned above, young age, PCOS, previous OHSS, high level of anti-Müllerian hormone (AMH), elevated serum estradiol (E2) are also considered to be risk factors for the development of OHSS (Haning et al., 1983; Forman et al., 1990; MacDougall et al., 1992; Mizunuma et al., 1992; Delvigne et al., 1993; Mordel and Schenker, 1993; Buyalos and Lee, 1996; Whelan and Vlahos, 2000). The gene discussed is AMH; the disease is polycystic ovary syndrome.