Parent‐child correlations for body measurements of children between the ages one month and seven years

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Abstract
SUMMARY: Measurement of height, weight, sitting height, biacromial and bi‐iliac diameters, bicondylar diameters of humerus and femur, upper arm circumference, and four skinfolds have been taken on a pure longitudinal series of 117 children at intervals from 1 month to 7 years, on the mothers of all of them and on the fathers of 57. The father‐son, father‐daughter, mother‐son and mother‐daughter correlation coefficients have been calculated at successive ages of the children.Most of these measurements show a steep rise in parent‐offspring correlation from the order of 0–2 at 1 month to the order of 0–4 at 2 years; from 2 to 7 a very gradual rise continues. Weight is an exception, the correlation being highest at 1 month, lowest at 9 months and subsequently rising. The parent‐offspring correlation for skinfolds from 3 to 7 years is only about 0–1, which does not differ significantly from zero.The mother‐daughter correlations for supine length in this age range are significantly above the mother‐son correlations. The same may also be true for weight after age 1, though the statistical significance is not fully established. In bi‐iliac and biacromial diameters no such sex difference occurs. The father‐son coefficient is greater than the father‐daughter coefficient for supine length, though not to a significant degree. The father‐son coefficient for biacromial diameter from 4 to 7 years is significantly above the father‐daughter coefficient.The conclusion is drawn that there are sex‐controlled genes affecting physique operating even before puberty. As there are usually supposed to be no mother‐daughter, mother‐son, etc., correlation differences in adulthood, the question is raised as to when and how these differences may be eliminated from 7 to 17 years. The published adult figures are also reexamined, with the conclusion that the supposed equality of the four parent‐child coefficients is much less securely based on evidence than is generally thought.There is a statistically significant correlation between skeletal maturity as assessed from wrist X‐rays at ages 3 and 5 of sons and the height of their mothers. Thus tall mothers have advanced sons; but they do not have advanced daughters. Similarly tall fathers have somewhat advanced daughters, but not sons. The cause of these correlations is not yet clear; in the adult there is no positive correlation between height and previous advancement in maturity.