A number of published observations on the maturation of the cranium have forensic applications. The size and closure of the various cranial fontanelles provide a rough estimate of skeletal age, as does the extent of ossification of the fetal skull. While dental aging is more useful in older infants, some early studies of the sequence and timing of deciduous teeth can provide information on fetal age. Other bones on which longitudinal studies provide some standards for age judgments include those of the hands and feet, the vertebral column, and the ossicles of the ear. Sexual differentiation begins early in fetal life. Male fetuses and neonates generally are heavier and longer. Additional studies suggest other sex differences in fetal and neonatal skeletons may parallel those found in older children and adults. 2 tables and 57 references.