Barbie was definitly an influence on me and as others here have mentioned--the supermodel craze. Today I think what most influences kids and adults are the magazines, tv, etc. because kids are actually veering away from standard toys like dolls in favor of the video games and cell phones they see supermodels and celebrities using. Personally, I'm 26 and I moderate my tv watching because that stuff really affects me.
It is sad to see that thin/curvy perfection is what is aspired to rather than happiness and health.