97 kindergartners and 2nd, 4th, 6th, and 8th graders were interviewed about their conceptions of 4 rule topics: sex-role stereotypes of toys, sex-role stereotypes of adult occupations, conventional table manners, and a natural law. Results indicate that Ss' knowledge of sex-role stereotypes and beliefs in the flexibility and cultural relativity of both sex-role stereotypes and a social convention significantly increased with age. Ss' beliefs in the flexibility and cultural relativity of a natural law decreased with age. Changes in conceptions of sex-role stereotype flexibility occurred concurrently with changes in social-conventional flexibility but were unrelated to changes in conceptions of the natural law. Findings suggest that sex stereotypes and social conventions are different aspects of the single conceptual domain of social convention.