The decline in age at puberty in the general population has been paralleled by an increase in the number of girls referred for evaluation of precocious puberty (PP). In 1999, The Lawson Wilkins Pediatric Endocrine Society recommended a lowering of the age limit for evaluation of PP in girls. However, the limited evidence on which these recommendations were based led many experts to question these new suggestions. The emergence of new European pubertal timing data evaluated by robust clinical as well as biochemical markers has broadened our insight on how to interpret the recent pubertal changes. The recent pubertal trends have resulted in a concomitant lowering of the lower limit of normality of the pubertal onset. However, evidence suggests that age at the gonadotropin and sex steroid surges have not changed. Thus, it looks as if an increasing proportion of contemporary early pubertal girls may experience isolated gonadotropin-independent thelarche rather than central PP, which may not be discernible on pubertal examination alone. Thus, the population-based limits of normality should not be directly translated into revision of age limits for evaluation of PP due to the risk of misdiagnosing rapid progressive PP as well as intracranial and other underlying pathology.

Based on this extensive data set, we found detectable AMH serum levels at all ages, with the highest measured levels during infancy. At the time of puberty, AMH concentrations declined and remained relatively stable throughout adulthood. The potential physiological role of AMH and clinical applicability of AMH measurements remain to be determined.

Methods: Anthropometric data from three contemporary Danish population-based studies were combined. References for height were based on healthy Caucasian children born at term. A total of 12 671 height measurements (8055 in boys and 4616 in girls) were included. Reference charts were developed using the generalised additive models for location, scale and shape.Results: From prepubertal ages, a secular increase in height was observed for both genders. The differences were most pronounced in puberty, and final heights were increased by 1.4 cm in boys and 2.9 cm in girls compared to 1982 references. In boys, but not girls an upward shift in body mass index (BMI) above median levels was found. Reference curves for height were superimposable with standard curves based on the selective WHO criteria. Danish children were longer/taller and heavier and they had larger head circumferences than those reported in the recent multiethnic WHO standards.

BACKGROUND AND OBJECTIVES: Studies of adolescents often use self-assessment of pubertal maturation, the reliability of which has shown conflicting results. We aimed to examine the reliability of child and parent assessments of healthy boys and girls.METHODS: A total of 898 children (418 girls, 480 boys, age 7.4-14.9 years) and 1173 parents (550 daughters, 623 sons, age 5.6-14.7 years) assessed onset of puberty or development of breasts, genitals, and pubic hair according to Tanner stages by use of a questionnaire and drawings. Physicians' assessments were blinded and set as the gold standard. Percentage agreement, k, and Kendall's correlation were used to analyze the agreement rates.RESULTS: Breast stage was assessed correctly by 44.9% of the girls (k = 0.28, r = 0.74, P , .001) and genital stage by 54.7% of the boys (k = 0.33, r = 0.61, P , .001). For pubic hair stage 66.8% of girls (k = 0.55, r = 0.80, P , .001) and 66.1% of boys (k = 0.46, r = 0.70, P , .001) made correct assessments. Of the parents, 86.2% correctly assessed onset of puberty in girls (k = 0.70, r = 0.71, P , .001) and 68.4% in boys (k = 0.30, r = 0.37, P , .001). Children who underestimated were younger and children who overestimated older than their peers who made correct assessments. Girls and their parents tended to underestimate, whereas boys overestimated their pubertal stage.CONCLUSIONS: Pubertal assessment by the child or the parents is not a reliable measure of exact pubertal staging and should be augmented by a physical examination. However, for large epidemiologic studies self-assessment can be sufficiently accurate for a simple distinction between prepuberty and puberty.WHAT'S KNOWN ON THIS SUBJECT: Many population-based studies including pubertal children are based on self-assessment of pubertal maturation, the reliability of which is uncertain.WHAT THIS STUDY ADDS: Self-assessment is not reliable for precise pubertal staging. Simple distinctions between prepuberty and puberty showed moderate agreement with clinical examinations. Parents and girls tended to underestimate and boys to overestimate pubertal development by up to 50% and 30%, respectively.

Analysis of the effect of multiple birth, birth order, age of parents and the sexes of preceding siblings on the secondary sex ratio was performed for 815 891 children, born in Denmark, 1980-1993. The proportion of males was analysed as a function of multiple birth, birth order, age of parents and the sexes of preceding siblings, using contingency tables, chi(2) tests and logistic regression analysis. The secondary sex ratio decreased with increased number of children per plural birth and with paternal age, whereas no independent effect was observed for maternal age, birth order, the sex of the preceding child, or the combination of sexes of previously born children in the family.

SF %BF showed the highest correlation and best agreement with DXA %BF in identifying children with excess fat (+1 s.d.).

Circulating AMH exhibits only minor fluctuations during childhood and adolescence, and a random AMH measurement seems representative for a given girl. The negative AMH-FSH correlation in prepubertal girls supports the notion that AMH is a quantitative marker of ovarian follicles even in young girls.

A recent decline in onset of puberty - especially among girls - has been observed, first in the US in the mid-1990s and now also in Europe. The development of breast tissue in girls occurs at a much younger age and the incidence of precocious puberty (PP) is increasing. Genetic factors and increasing prevalence of adiposity may contribute, but environmental factors are also likely to be involved. In particular, the widespread presence of endocrine-disrupting chemicals (EDCs) is suspected to contribute to the trend of earlier pubertal onset. The factors regulating the physiological onset of normal puberty are poorly understood. This hampers investigation of the possible role of environmental influences. There are many types of EDCs. One chemical may have more than one mode of action and the effects may depend on dose and duration of the exposure, as well as the developmental stage of the exposed individual. There may also be a wide range of genetic susceptibility to EDCs. Human exposure scenarios are complex and our knowledge about effects of mixtures of EDCs is limited. Importantly, the consequences of an exposure may not be apparent at the actual time of exposure, but may manifest later in life. Most known EDCs have oestrogenic and/or anti-androgenic actions and only few have androgenic or anti-oestrogenic effects. Thus, it appears plausible that they interfere with normal onset of puberty. The age at menarche has only declined by a few months whereas the age at breast development has declined by 1 year; thus, the time span from initiation of breast development to menarche has increased. This may indicate an oestrogen-like effect without concomitant central activation of the hypothalamic-pituitary axis. The effects may differ between boys and girls, as there are sex differences in age at onset of puberty, hormonal profiles and prevalence of precocius puberty.