Numerous studies have suggested that sex hormones, especially oestrogens, can contribute to the onset and development of the disease activities of systemic lupus erythematosus (SLE), and this seems to be associated with the gender bias of SLE. In fact, there is significant evidence of the inductive effects of oestrogens on autoimmune-related immune responses, such as the production of antibodies, cytokines, and autoantigens including human endogenous retroviruses (HERV). The higher susceptibility to oestrogens in patients with SLE may be regulated by quantitative/qualitative abnormalities of oestrogen receptors (ERs) and different immune responsiveness to oestrogens in SLE patients in comparison to normal controls. In addition to previous findings, this report reviewed and discussed possible the mechanisms of gender bias of SLE based on results obtained by recently developed technologies such as DNA microarray methods.