Liang Z, Liu H, Wang L, et al. - Researchers examined the relationships between maternal gestational diabetes mellitus (GDM) and genetically determined maternal BMI during pregnancy on offspring childhood obesity. From August 2009 to July 2011, they included a total of 1,114 Chinese mother-child pairs (560 GDM and 554 non-GDM). Based on 12 single nucleotide polymorphisms identified from a genome-wide association study, derivation of maternal genetic risk score (GRS) of BMI during pregnancy was done. Measurement or calculation of offspring’s BMI, BMI-for-age z score, weight, weight-for-age z score, waist circumference, sum of skinfolds, and body fat percentage during childhood was performed. After multivariable adjustment, per unit of GRS was noted to be linked with a 24% and a 28% elevated risk of overweight and obesity among children of GDM mothers. Moreover, among children of GDM mothers, per unit GRS of BMI during pregnancy was significantly linked with 0.16 kg/m² higher BMI, 0.09 higher BMI-for-age z score, 0.24 kg higher weight, 0.06 higher weight-for-age z score, 0.28 cm higher waist circumference, 0.94 mm higher sum of skinfolds, and 0.37% higher body fat percentage. These findings, for the first time, suggest that relation between genetically determined maternal BMI during pregnancy and offspring’s obesity risk during childhood may modify due to maternal GDM status.