Analysis of sibling resemblance in anthropometric somatotype components

We analysed the Heath-Carter somatotype familiar resemblance degree in a sa mple of 1350 siblings (685 males and 665 females) from 634 nuclear families in the province of Biscay (Basque Country, Spain). Sibling correlations we re estimated according to maximum likelihood procedures for endomorphy, mes omorphy, ectomorphy and somatotypical attitudinal distance (SAD(i)), after having adjusted for age, sex and the two other components (Model I), and af ter taking into account several environmental variables shared by all membe rs of each sibship (Model II). All sibling correlations of the somatotype c omponents were significant, tending to be higher in the case of mesomorphy than in the case of endomorphy. Same-sex siblings (BB and SS) displayed sig nificant mesomorphic and ectomorphic resemblances, but in the case of endom orphy, sisters (SS) revealed relatively low correlation compared with broth ers (BB). The sex of sibs had a significant influence on correlations of me somorphy, but not on the other two components. Further control of socio-fam ilial variables such as the father's occupation and education, and the sibs hip size, resulted in lower mesomorphy correlation coefficients, but had no effect whatsoever on the other two components. SAD(i) correlations were ve ry low and not significant, indicating high degrees of dispersion in the in dividual somatotypes of the sample.