Animal models using ovariectomy (OVX) to mimic postmenopausal osteoporosis are widely used to study the mechanisms involved.(18) Conditional knockout mouse models deleting estrogen receptor alpha (ERα) in various mesenchymal cell types further underline the importance of estrogen for bone, since both Paired related homeobox (Prx)1‐Cre and Osterix (Osx)1‐Cre ERα knockout mice suffer from bone loss.(19) Deletion of ERα in mesenchymal progenitors using Prx1‐Cre mice led to increased osteoclastogenesis, which resulted in cortical bone loss. This evidence concerns the gene ESR1 and postmenopausal osteoporosis.