[Some indicators of lineal and craniofacial proportionality in newborn infants]

Looking for intersexual differences in size and lineal and craniofacial proportionality, assumed to be secondary to genetic induction, non-distorted by environmental factors, we studied 200 newborns from families who were residents in proletarian zones, parents with very similar education and employment (qualified workers). We chose 15 size measurements from which we derived 23 ratios and 15 craniofacial measurements with four key indices. Significant but discrete intersexual differences were found in height and in cranial circumference, and larger differences in leg, foot, forearm and arm length; there were no differences in the proportionality indices. In eight of the 10 craniofacial measurements there were intersexual differences, but not on the ratios derived from them. We conclude that as an expression of genetic induction (accepting "size" as a phenomenon of accumulated growth, and the "ratios" of development or differentiation) what we found confirms other studies that point out that when a boy is born, he is bigger in size but less developed than the girl.