Later in life, sex differences in aromatase may affect risk for neurological diseases, such as depression and AD, which tend to be greater in females than males (Dalla et al., 2004; Ordyan et al., 2007; Overk et al., 2012; Lu et al., 2015; Alarcon et al., 2017; Kokras et al., 2018). This evidence concerns the gene CYP19A1 and major depressive disorder.