Isogenic male (■) and female (Ο) C57BL/6 mice had normally distributed birth weights (A, N = 334 mice, W = 0.99). Neonatal weight gain was inversely proportional to litter size (B, N = 57 litters, R = 0.94). Fetal or neonatal growth restriction was defined by a weight below the 10th percentile at 2 days (C) or 20 days (D). Using this definition, mice were categorized as having appropriate fetal and neonatal growth (AA, ■, N = 15 males and 14 females), restricted fetal growth but appropriate neonatal growth (RA, ▨, N = 6 males and 8 females), or restricted fetal and neonatal growth (RR, □, N = 7 males and 6 females). * p<0.01 versus control