Results from these large-scale studies are confusing (Shapiro, 2007). An overview of the results based on what type of HRT women were taking is presented in STable 13.3. A newer approach to HRT involves a class of compounds called selective estrogen receptor modulators (SERMs), which can be considered "designer estrogens" in that each has its own way of acting and so must be evaluated individu- ally (Shelly et al., 2008). s have the protec- tive properties of estrogen on bone tissue and