Lai Y, et al. - Given a significant and positive link of maternal family history of diabetes with birth weight in grandchildren, researchers investigated the effect of grandparental diabetes on the grandchild’s body mass index (BMI) at infancy peak (IP) and obesity status at age 2. They gathered family diabetes mellitus (DM) information from Ma’anshan Birth Cohort Study and retrieved the height and weight of children from medical records. They plotted BMI at 6 points (0, 3, 6, 9, 12, 18 months) for every child. In this sample, DM was reported in about 6% of the maternal grandfathers, mean of infancy BMI peak was 18.37 kg/m2, and 6.6% of the children were obese at age 2. The IP BMI values could be significantly increased by a maternal grandfather with DM, which was also linked to obesity status at age 2. However, no relation with maternal grandmother and paternal grandparents was identified. Ultimately DM in a maternal grandfather was identified as a risk factor for high BMI at peak and obesity at age 2in the grandchild.