The consequences of a poor intra-uterine environment during pregnancy are known to be deleterious to the offspring. The problems may range from diabetes to cancer and beyond. Most women are willing to accept that their choices during pregnancy will certainly affect their offspring, and many willingly take preventative steps such as the cessation of smoking and alcohol consumption to improve the health of their child. As such, it is surprising that little emphasis seems to be placed on actively fostering a positive environment for fetal development, be it through dietary manipulation or exercise. Consumption of a high-fat (HF) diet during pregnancy may have significant impact on the unborn child, causing high birth weight and glucose intolerance among other problems, not to mention the negative effects on the pregnant woman. The goal of the first Aim of this study is to establish a mouse model of maternal HF diet-induced obesity and glucose intolerance in offspring. We have previously shown that exercise during pregnancy significantly improves insulin sensitivity in aged mouse and rat offspring when both dams and offspring consume a standard diet. We hypothesize that exercise during pregnancy will prevent the negative consequences of maternal and offspring HF feeding. While individuals often fail to exercise for their own benefit, perhaps women would be more willing to increase physical activity for the sake of their unborn child.