Most of the data on potential favourable effects of LH activity on oocyte/embryo quality and on the endometrium are based on superovulating patients undergoing in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI) cycles or oocyte donors, which usually exclude patients with PCOS (Acevedo et al., 2004; Platteau et al., 2004; Lisi et al., 2005; Smitz et al., 2007; Ziebe et al., 2007; Weghofer et al., 2008; Huddleston et al., 2009). This evidence concerns the gene PLOD1 and polycystic ovary syndrome.