The protective effect of estrogen on β‐cell function is thought to be mainly due to estrogen receptor activation, which promotes survival and β‐cell mass expansion in rodents (Bernal‐Mizrachi et al., 2014) and may improve β‐cell mass in type 1 diabetes (Mauvais‐Jarvis, 2016). This evidence concerns the gene ESR1 and type 1 diabetes mellitus.