Variation in the extent an attitude is imbued with moral conviction is a strong predictor of a variety of consequential social judgments; however, the extant literature has not explained variation in moral conviction. The authors predict that some attitudes may be experienced as moral because they are heritable, promoting group survival and firmly rooting people in these attitudes. To test this hypothesis, the authors surveyed two community samples and a student sample (total N = 456) regarding the extent participants perceived 20 attitudes as moral attitudes, and compared these ratings to established estimates of attitude heritability. Across all three studies, attitudes with greater previously established heritability estimates were more likely to be experienced as moral, even when controlling for a variety of measures of attitude strength and the extent to which an attitude is associated with one’s religious beliefs.