From Al Mohler:
But the most basic problem with Barbie is the fact that she lies. Constantly. The entire Barbie package presents one huge lie about the nature of true beauty. According to the Christian worldview, beauty and truth and goodness are identical. A lie cannot be beautiful and the truth is never ugly. Barbie’s total presentation represents a lie about feminine beauty, suggesting in not-too-subtle ways that external attractiveness (even artificial attractiveness) is the foundation of true beauty.
But, according to the biblical worldview, genuine beauty is found within – in the being and character of a person – not in their external appearance. The first principle of human beauty is the fact that every human being, male and female, is made in God’s image. No one made in God’s image can be anything less than beautiful.