Mother's Union was speaking after the research, which looked at 6,000 children, found that kids as young as eight were unhappy with their bodies. Specifically, 5% of girls and 3% of boys aged eight didn't like their bodies.
This went up to 32% of girls - nearly a third - and 16% of boys by the time they turned 14.
The study also found a link between low self-esteem in early years and eating disorders, with 39% of girls - almost four in ten - and 12% of boys developing them by the age of 14.
It also found that low self-esteem in women was not always linked to weight, with girls in the study developing eating disorders regardless of whether they were overweight or not.
Mother's Union has said parents are increasingly aware of the body image issues of their children, however they often lack the resources required to address the problem.
The charity also said two-thirds of parents felt advertising was to blame for self-esteem issues with children - particularly females - because of the standards of beauty and physical figures it shows, and the emphasis it puts on being sexually attractive.
Fiona Thomas, from Mother's Union, told Premier: "We know that advertising is very much a concern for parents... We had a young girl in the ComRes research [we did]... who said 'I've got fat thighs, I've got fat legs', at the age of eight. So it's something that's really affecting children, and parents very much pinpoint advertising."
Commenting on the fact far more girls than boys developed eating disorders in the study, Fiona said: "Mother's Union... and this study show that there is a wider issue than just girls [being more affected].
"We know that half of all girls believe that they need to be attractive to the opposite sex, and that's very young girls, that that's one of their roles, and that's very disturbing. We're giving young women and young girls the wrong message."
"But equally, by doing so, we're giving boys the wrong message... It still manifests itself in poor gender equality issues, it manifests itself in the way men might treat girls in future relationships, what they're looking for in a life partner. So the impact on wider family life for generations might be affected."
Listen to Premier's Aaron James speaking to Fiona Thomas here:
