In PCOS women undergoing CC treatment, a high endogenous LH concentration prior to treatment has been associated with a high probability of conceiving (Kousta et al., 1997; Imani et al., 1999), whereas elevated endogenous LH concentrations during the follicular phase of CC treatment have been associated with poor treatment outcome (Shoham et al., 1990). The gene discussed is PLOD1; the disease is polycystic ovary syndrome.