When young girls play with Barbies they start to compare themselves to the doll whether they realize it or not. Soon they aspire to look like the doll and have the perfect hair and body. Soon they understand that they can't match the perfect figure and begin to feel ugly and worthless. Barbies are destroying self-esteem of young children and taking away their innocence.
My cousins and I knew as children we wouldn't grow up to look like our barbie dolls because our mothers told us that's not how women look. If you tell your children "Honey Barbie is pretty but that's not a real figure" and explain it to them then and make sure they know they will be beautiful if they don't look like her (and the Photoshop images of women in other media) then they'll accept their bodies when they don't turn out that way.