This study evaluated intraindividual child-adult and interindividual child-parent relationships of body mass index (BMI) using data from the Trois-Rivières semilongitudinal study of growth and development. Intraindividual correlations between age 12 and 35 years were substantial (r(2) = 36% of variance in women, 30% of variance in men). Interindividual child-parent correlations for mothers and fathers age 36.6 +/- 0.4 and 39.5 +/- 0.4 years, respectively, were very low to low for daughters age 12 years (r = 0.09, NS and 0.34, P