It was reported that the concentration of Th1 cell-related cytokines like interferon-γ (IFN-γ) was lowly expressed, while Th2 cell-related cytokines like interleukins (IL)-4, IL-10, and IL-13 were highly expressed in the serum of the patients with endometriosis [10, 11]. This evidence concerns the gene IFNG and endometriosis.