Children whose parents are married are HALF as likely to be obese Those with married parents have a 17% chance of obesity, those with cohabiting parents have 31% risk 23% of children who live with single mother are obese, compared to 15% of those living with a single father May be because single fathers tend to be more affluent American scientists found that children who live with cohabiting parents are twice as likely to be obese as those with married parents Children with married parents are less likely to be obese, according to new research. American scientists found that children who live with cohabiting parents are twice as likely to be obese as those with married parents. The research, by Rice University in Houston and the University of Houston, shows that children living in a traditional two parent married household have a 17 per cent chance of obesity. In contrast, children living with cohabitating parents have a 31 per cent chance of obesity. "Childhood obesity is a significant public health issue in our country, with nearly one third of all U.S. children aged two to 17 overweight or obese," said Dr Rachel Kimbro, study co-author and associate professor of sociology at Rice University. Despite this, very little research has been conducted to explore the impact of family structure on this epidemic. The researchers also found that 29 per cent of children who live with an adult relative are obese, 23 per cent of those living with a single mother are obese, and that 23 per cent of those who live with a cohabiting stepparent are overweight. The findings held true even after the researchers accounted for factors associated with childhood obesity, including diet, physical activity and socio-economic status. The exception to the rule was children living with single fathers or in married stepparent households, who had an obesity rate of 15 per cent. "Previous research has shown that single-father households tend to have more socio-economic resources than single-mother households," Dr Kimbro said. And since socio-economic status is the single greatest predictor of health, it serves to explain why children in single-father households may be less likely to be obese. Children with married parents have a 17 per cent chance of obesity, in contrast, children living with cohabitating parents have a 31 per cent chance of obesity The study examined the obesity rates of children living in traditional and non-traditional family structures in the U.S. The research sample of 10,400 children came from the Early Childhood Longitudinal Study-Birth Cohort, a nationally representative study of U.S. children and their families designed to provide information on children's development. The primary caregivers of the children participated in the first wave of interviews when their children were approximately nine-months-old. Data was subsequently collected when the children were two-years-old, four-years-old, and in kindergarten. The researchers also found that 29 per cent of children who live with an adult relative are obese, 23 per cent of those living with a single mother are obese, and that 23 per cent of those who live with a cohabiting stepparent are overweight The interviews included assessments of the children's height, weight and other measures of development, such as cognitive functioning. The children were organised into eight mutually exclusive categories designed to account for the children's current family structure and the one they were born into. "For reasons we cannot fully measure, there appears to be something about people who marry and have a child that is fundamentally different than the other groups, and these factors are also linked to children's weight," Dr Kimbro said. "Our hope is that this research will encourage further exploration of this topic," said Dr Kimbro's co-author, Dr Jennifer Augustine. There is substantial research on how family structure matters to other domains of children's development, yet little research on why marriage and other family structure types might matter for children's obesity.