Female and male mice hippocampal gene expression changes with age. In female brains, 44.2% (73 genes; 23 increase, 50 decrease), 10.9% (18 genes; 3 increase, 15 decrease), and 6.1% (10 genes; 9 increased, 1 decreased) of genes showed significant changes between the ages of 6 months and 9 months, 9 months and 12 months, and 12 months and 15 months, respectively. In contrast, in male brains, 5.4% (9 genes; 2 increase, 7 decrease), 5.4% (9 genes; 4 increase, 5 decrease), and 27.3% (45 genes; 35 increase, 10 decrease) of genes were significantly changed from the ages of 6 months–9 months, 9 months–12 months, and 12 months–15 months, respectively.