We've probably all heard that Barbie's (TM) measurements are not just unattainable but dysfunctional. She's so top heavy that she'd tip over when she walked, her waist cavity is too small to support her internal organs, etc etc. A sophomore at Hamilton College, Galia Slayen, drives this home with a 6-foot tall doll of Barbie made to scale.
(Image from Hamilton College news story linked below.)
The accompanying story is about eating disorders. Although I think it's plausible that playing with Barbie affects girls' body image and later risk for eating disorders, we still lack convincing evidence of the causal link. Problem is, we may never get it. The most convincing research design would randomly assign a cohort of girls to two groups, one that plays with Barbies and one that doesn't. (Ideally, the researchers would be able to control access to images about Barble as well, e.g., on TV, but this would be virtually impossible from a practical and ethical standpoint.) The researchers would then track the girls as they grow up, and calculate whether the "Barbie" group is more likely to develop eating disorders. The sample would have to be fairly large in order to have enough power to derive meaningful probabilities, because eating disorders are still relatively low probability events. This study would be extraordinarily expensive, and somehow I don't see Mattel coughing up the bucks to fund it. So, we're left with correlations, at best.
To be fair, this wasn't Galia's point. Her goal was to raise awareness about eating disorders on her campus, and the life-size Barbie doll was a good "hook" to get people to listen. Major kudos to her and her friends for trying to make a difference.