The included factors were maternal age (continuous variable), paternal age (continuous variable), BMI (continuous variable), gravidity (continuous variable), duration of infertility (continuous variable), type of infertility (primary/secondary infertility), infertility diagnosis (tubal/male/both/others), PCOS (yes/no), basal antral follicle count, basal serum FSH level, fertilization method (IVF/ICSI), endometrial thickness on the first day of progesterone administration (continuous variable) and type of transferred embryos (cleavage embryo/blastocyst). This evidence concerns the gene BRD2 and polycystic ovary syndrome.