RATE OF GROWTH IN RELATION TO BIRTH RANK AND FAMILY SIZE.

Abstract

This article examines data from a 9-year growth study for evidence of the effect of birth rank and family size. Growth records were kept for 1061 London families rehoused on a London County Council estate in Hertfordshire England. The study found that height gains between the ages 6 and 10 were less in large families than in small ones. There was a tendency for each successive child in a family to be taller than the preceding siblings between the ages 6 and 11; but despite this mean height and weight for ages 6 to 10 decreased as family size increased. The more children in a family the further the height of the first-born fell behind that obtained by only children of comparable age. Several possible explanations were examined. One is that the overall nutrition of smaller families. Another is that children from large families are subject to increased infection conveyed by older siblings. Evidence conflicts but 1 study holds that even illnesses that last just a few weeks involve a loss in expected stature of 1/4 inch in a years growth with no evidence of subsequent acceleration. Another possible inhibiting factor in growth attainment is that children in large families get less rest and less feeding up after an illness than children from small families. The role of 2 other factors examined general growth trends in the community and heredity - cannot be determined.