From a sample of 895 girls from Bilbao 9.5 to 18.5 years of age, the possible influence of family size and birth order on menarcheal age was analyzed. The earliest mean ages of menarche occurred in girls from families of one or four or more children, or who occupied the first or last birth order in their families. Later mean ages of menarche occurred in girls belonging to sibships with two or three children or who occupied the second or third birth order in their families, the latest being girls belonging to sibships of three children or of third birth order. This may be due to the variations in the interval of time between births, leading to better care and less stress for the youngest individual of the family and, hence, may be indicative of psychological as well as biological factors affecting maturation. Am. J. Hum. Biol. 11:779–783, 1999. © 1999 Wiley‐Liss, Inc.

Data on menarcheal age were collected by the status quo method on a sample of 894 schoolgirls (9-19 years of age), from the Biscay province coast (Basque Country, Spain). Logit analysis provided a mean age at menarche of 12.75 +/- 0.04 years with a standard deviation of 0.93. The result was compared with data from another previous Basque study.

The association between fat distribution and Heath-Carter anthropometric somatotypes was studied in a sample of Basque children and youth aged 8-19 years. About mid-adolescence, mean somatotype of Basque males changed, diminishing in endomorphy and mesomorphy, and increasing slightly in ectomorphy. For the same period, reduced mesomorphy was the most striking change in the female mean somatotype; meanwhile, there was an increase in endomorphy and a decrease in ectomorphy. Two groups of fat distribution were identified: centripetal and peripheral. Centripetal fat increased with age in both sexes. Fat distribution groups showed the following characteristics: a) mean somatotypes of centripetal and peripheral subjects were significantly different; b) centripetal boys and girls were extreme endomorphs prior to adolescent somatotype change; c) centripetal girls showed high ratings of endomorphy after adolescence; d) mesomorphy was related to a centripetal fat distribution pattern in both sexes; e) using the BMI as a criterion of obesity, only 16.3% of centripetal males and 21.8% of centripetal females were classified as obese; f) obesity was absent among subjects with a peripheral pattern, except for one male showing an endomorphic-mesomorph somatotype; h) the obese showed extreme somatotypes with high endomorphy and mesomorphy, and minimal ectomorphy. © 1994 Wiley-Liss, Inc.

Skin colour variation with increasing age was analysed using a cross-sectional sample of 796 Basque boys aged from 8 to 19 years. Measurements were taken at the upper inner arm and forehead by means of an EEL DS29 Digital Unigalvo reflectance spectrophotometer with a nine-filter head. Ontogenic changes of skin pigmentation were found to be statistically significant. The influence of the month in which measurements were taken on reflectance values has been studied. Comparisons with another similar study (Pembrokeshire, Wales population) were carried out.

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