A child's risk of becoming an obese adult is strongly influenced by parental obesity in either the mother or father. For children under 10 years old, whether obese or not, having an obese parent more than doubles the risk of adult obesity. The toddler who's overweight but whose parents are of normal weight has a 90% chance of not being an obese adult, or a 10% chance of adult obesity. But toddlers who are overweight and have at least one parent who's overweight, their risk goes up to 40%.

The New England Journal of Medicine September 26,1997;337:869-873

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