China's Obesity Problem Linked To Single Child Policy

"What they found was that only-sons had significantly greater BMI and were at greater risk (23 percent) of overweight and obesity than sibling-sons. Overall, the only-sons reported less time spent in watching TV and using the internet than sibling-sons. Further, the weight trend was accentuated in only-sons from urban areas — they were 36 percent more likely to be overweight and 43 percent more likely to be obese than were urban sibling-sons.

Analysis of girls’ data indicated that only-daughters had a higher risk of obesity (43 percent) than sibling-daughters, but this difference wasn’t statistically significant — even when urban and rural girls were examined separately."