Oestrogen receptors (ER) are emerging as important molecules involved in the variety of physiological and pathological activities. There are two classic oestrogen receptors: alpha and beta. Different cells and tissues have shown divergent responses to these two oestrogen receptors. While we are starting to understand the interaction between oestrogen receptors and its ligands contributes to the development of various diseases, the discovery of sub-isoforms of oestrogen receptor alpha and beta has further complicated the mechanism of oestrogen receptors. Nevertheless, continuing efforts in the...