This study examined the secular changes in height, body weight, body mass index and pubertal development in male children and adolescents in Krakow (Poland) over the past 80 years, with an emphasis on the last decade (2000-2010). The survey of the population of Krakow is a continuation of observations conducted in that area for many years. The analysis aims to determine whether in the last decade Krakow still witnessed the secular trend, and what form the trend took. The body height and weight, and body mass index (BMI), of 1862 boys aged 3.5-18.5 years were analysed, against the background of a survey series from the years 1938 (N = 1801), 1971 (N = 2045), 1983 (N = 3124) and 2000 (N = 2328). The mean body height, in almost all age categories, was greater than in the past; however the final height over the last decade remained the same. The mean values of body weight and BMI increased, especially in the last decade. Also, an acceleration of puberty in boys was observed. The last 10 years saw an over 3-month decrease in the age of initial appearance of pubic hair in boys. In conclusion, the last decade saw cessation of the growing taller trend: maximum body height stabilized at approximately 179 cm, but weight and BMI increased. Also, a distinct acceleration of puberty was noticed. Lack of height increase, at the same time as weight gain and puberty acceleration, indicate a progressing developmental disharmony.

Objectives: This survey aimed at analyzing secular changes in the development of girls from Krakow, in the first decade of the 21st century, against the background of transformations observed in the previous century. Methods: The data collected during a survey conducted in Krakow in 2010, in which the measurements of a total of 1,974 girls aged 3.5–18.5 years were taken, made a basis for this study. The results from the contemporary series were compared with previous surveys conducted in 1938, 1971, 1983, and 2000. The analysis of the survey made use of the results of body height and weight measurements, BMI, and the menarche, thelarche, and pubarche onsets determining the level of pubertal development. The development of secondary sex characters was assessed utilizing the criteria 5‐stage scale established by Tanner. The mean age of the menarche onset and ages at beginning breast (B2) and pubic hair (PH2) development were calculated by means of the probit method. Results: In the physical development of girls a positive trend in body height changes in prepubescence and adolescence was still observed. The acceleration of body weight development in peripubescence is expressed by increased BMI. It is spectacular that body build gets slimmer at the age of 17 and 18, which is probably connected with conscious control of body weight, and pubertal acceleration is also maintained. Conclusions: Still observed trends in morphological factors and pubertal acceleration require further monitoring out of concern for the health and proper development of children and adolescents. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.

The purpose of this study was to see whether menarcheal age assessment by means of the most frequently used methods that were conducted every time on the same group of girls would yield the same results. One hundred and one Polish girls, whose ages at menarche were recorded in a longitudinal study between 1976 and 1990, were asked to recall the age of menarche in 2004. The mean menarcheal ages of those women were calculated by means of the probit (PA), prospective (AA), retrospective method without age correction (RA), and retrospective method with the recall age corrected by 0.5 year (RcA). The PA, AA, and retrospective methods: RA and RcA revealed results: 13.14 +/- 1.1; 13.10 +/- 1.1; 13.12 +/- 1.36, and 14.39 +/- 1.34 years, respectively. The menarcheal AA was insignificantly different from the PA (95% CI) and RA. The RcA was significantly higher than the AA and RA (P = 0.05). The correlation coefficient (r) between AA and RA was 0.70. Only 16% of the interviewed women accurately remembered the date of their menarche, 63% of them missed their menarche time by about 1 year, whereas 22% were wrong by 2 and more years. (1) The PA and the AA method yield comparable results when estimating menarcheal age. (2) The menarcheal age determined by the retrospective methods is not very reliable and the application of age correction overestimates the results.

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DO MONOZYGOTIC TWINS HAVE IDENTICAL GENOTYPES? Recent observation of the fertilization process and further embryonic development concerned with the fate of spermatozoon mitochondria, as well as the results of studies on genetic mechanisms of differentiation and cooperation between the nuclear and mitochondrial genomes allow to conclude that monozygotic twins do not have identical genotypes. One of the evidences is the development of hereditary diseases in only one of such twins.