Surveys reveal that Chinese from the southernmost provinces are, on average, consistently shorter and lighter than their peers in provinces to the north, though explanations for this variation differ. The present study helps to distinguish between genetic and developmental explanations by comparing differences in regional and provincial heights and weights of 3184 children born in Taiwan between 1975 and 1980 whose families had emigrated from different regions of China at varying times in the past, but who all lived in a relatively affluent district in Taipei at the time of measurement. Linear regression analyses adjusted heights for measurement age and relevant (and available) socioeconomic and demographic variables. Results of these analyses suggested that clinal genetic variation is an important contributor to regional differences in China. Whether entering primary school or departing middle school, children of northern Chinese ancestry living in Taipei were significantly taller (males, 25-30 mm, p0.014; females, 18 mm; p0.008) and heavier (males, 2.5-3.8 kg; p0.081; females, 0.9-3.4 kg, p0.046) than those of southern ancestry, with those from central provinces intermediate in most comparisons. Additionally, provincial backgrounds of Taipei middle school girls with family origins in 12 provinces across China and in Taiwan were significantly associated with height (n=905; p=0.003) and weight (n=900; p=0.001). The pattern of change in mean values across provinces of origin suggests that as developmental circumstances become more equal for residents of various provinces in China, already documented declines in mean height differences, particularly in some central and southern provinces, will shrink further.