This study focuses on unsanctioned births?fertility that violates family planning regula
tions ? in China. A theoretical framework is established, based on the cultural conflict perspective of
deviance. The normative conflicts between the traditional norms of large family sizes and current
family planning rules are explicated. The China's In-Depth Fertility Survey, with a sample of 6,654
Chinese ever-married women aged 49 or younger, is used to explore the relationships between
unsanctioned births and socioeconomic development, influences of the traditional fertility norms and
previous reproductive experiences. Multivariate analysis findings indicate that the traditional ideal
of large family sizes, son preferences, socioeconomic development, types of employment, areas of
residence, failed pregnancies and fertility discussions between husbands and wives are significantly
related to unsanctioned births. In addition, the analyses reveal different patterns between rural and
urban samples in terms of the impacts of individual variables on unsanctioned fertility, and different
explanatory powers of the models. Several relevant issues drawn from the findings are discussed,
including the relationships between unsanctioned births and rural-urban differences as well as the
normative conflicts of fertility in China.