This translational research study will obtain paired measures of metabolic flexibility (postprandial RQ minus basal RQ) in response to a standardized meal by indirect calorimetry in mother:infant dyads of diabetic and non-diabetic pregnancies. The downstream effects of the intrauterine exposure to diabetes and gestational lipotoxicity will be tested in the infant: 1) at birth by studying adipogenic pathways and mitochondrial function in umbilical cord mesenchymal stem cells cultured in myogenic conditions[13], and 2) by studying metabolic flexibility in the infant in a whole body infant calorimeter in response to a standardized meal.