Nature versus nurture in dento-facial variation

The relationship between genetic and non-genetic factors in the aetiology of dentofacial variation and malocclusion has previously been studied in both twin and family investigations. The aim of such studies has been to determine the heritability (role of genetic factors in the total variability) of different characteristics or combinations of characteristics. The necessity for caution in interpreting calculations of this kind is stressed. Some investigations indicate that 40% of the total variance might be due to genetic factors. Further research is necessary, however, to decide to what extent these results may be due to so called cultural inheritance, depending on family related environmental factors. A path analysis of 42 pairs of twins was performed with respect to facial height and facial depth. The comparison as to any differences in heritability or cultural inheritance proved to be inconclusive.