On the intra-pair similarity of Japanese monozygotic twins in some somatological traits.

Intra-pair similarity of some somatological traits was analysed about 59 male and 69 female Japanese monozygotic twin-pairs aged between 12.25 and 13.25 years in terms of intraclass correlation coefficient (r') as well as Coefficient of Similarity (CS). Among 28 anthropometric measurements, the stature, body weight and iliospinal height consist of the highest similarity group, while skinfold thicknesses, calf fat thickness (X-ray) and some cephalic measurements belong to the lowest. Among 26 indices, relative body weight, Kaup, Rohrer, cephalic modulus are high, and intermembral index, abdominal index, acromio-cristal index are low in similarilarity. For circumferencial sizes, both absolute and relative, the male similarity is noticeably higher than the female one. Physiological ages, including skeletal, menarchial and peak height velocity, represent a high similarity. In calf tissue composition analysis, Bone is high, Fat is low, and Muscle is intermediate in similarity. The relation of the similarity with the so-called heritability was discussed.