We examined the expression of m6A and methyltransferase-like 3 (METTL3) in endometrial samples taken from normal fertile women in the proliferative phase (the NP group) or the mid-secretory phase (the NS group) or from women with endometriosis-related infertility at the mid-secretory phase (the ES group). The gene discussed is METTL3; the disease is Infertility.