Approximately 25 % of US 2-to-5-year olds are overweight and ethnic minority groups are disproportionately affected. We explored the relationship between parent demographic characteristics, various perinatal/early childhood (EC) factors, and child body mass index (BMI) to determine possible contributors to these disparities. A preschool-based randomized controlled (N = 28 centers) obesity prevention intervention was conducted among multiethnic 2-to-5 year olds. Baseline assessment of demographic characteristics, various perinatal/EC factors, and child BMI were analyzed via generalized linear mixed models and logistic regression analysis. Foreign-born parents were almost 2.5 times as likely to have an obese child versus children of US-born parents (OR 2.43, 95 % CI 1.53-3.87). Families who spoke Spanish only or a combination of Creole/English at home were over twice as likely to have an obese preschool child versus families who spoke English only at home. Parent place of birth and language spoken at home plays a significant role in early childhood obesity. Future early childhood healthy weight initiatives should incorporate strategies that take into account these particular parent characteristics. [ABSTRACT FROM AUTHOR]