On the newsfeeds today is a story about linking your future child's weight to the weight you might gain during pregnancy. What the study found was the children of women who gained more weight during pregnancy had a higher likelihood of being overweight at age 3.
The conclusions being drawn on the newsfeeds is that the issue of obesity in North America must therefore be due to weight gain during pregnancy. The fact is there are literally thousands of variables that affect weight and even more that affect eating behaviour.
Interestingly the only controls mentioned in the experiements were for race, parental smoking, household income and fetal growth during pregnancy. The only control I would want to know about is the eating habits of the household to begin with because guess what, children eat what parents buy and if the household has calorie dense choices, parental inactivity and poor nutritional education that's far more of a culprit in childhood obesity than anything else.
By far the best way to help your children is to live well yourself and let them learn from you.