OBJECTIVE: To assess the relationship between the measures of body weights of parents and those of their children during the ®rst two years of life. SUBJECTS: Seventy-eight infants born to obese (`high risk') or nonobese (`low risk') mothers. METHODS: Weight, weight for length and skinfold thicknesses of the high and low risk infants were measured at 3 months, 12 months and 24 months of age. A multiple linear regression analysis assessed the contributions of nine risk factors, including paternal and maternal body mass index (BMI: kgam 2 ), to the weight and weight for length of infants at 12 months and 24 months of age. RESULTS: There were no differences between the high and low risk groups in weight, weight for length or skinfold thicknesses at 3 months, 12 months or 24 months of age. Neither paternal nor maternal BMI entered the multiple regression. CONCLUSIONS: These results suggest that genetic in¯uences on the body weight of infants may be independent of those that in¯uence BMI in adults, a circumstance that could complicate the search for genetic determinants of obesity.