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. (1970), Archives of Disease in Childhood, 45, 13. Variations in the pattern of pubertal changes in boys. Mixed longitudinal data on the physical changes at puberty in 228 normal boys are presented together with normal standards for stages of genital and pubic hair development.The genitalia began to develop between the ages 91 years and 131 years in 95% of boys (mean = 11 -6 ± 0 09) and reached maturity at ages varying between 13 and 17 (mean = 14-9 ± 1 10). The age at which pubic hair first appeared was not accurately determined, but its development through the later stages was studied. It reached the equivalent of an adult female distribution at a mean age of 15'2 ± 0-01 years.On average the genitalia reached the adult stage 3 * 0 years after they first began to develop; but some boys completed this development in as little as 1 * 8 years while others took as much as 4 * 7 years. Some boys complete the whole process in less time than others take to go from Stage G2 to Stage G3. The genitalia begin to develop before pubic hair is visible in photographs in practically all boys.The 41 boys in whom it could be studied reached their maximum rate of growth (peak height velocity) at a mean age of 14i 1 ± 0 14 years.Very few boys (about 5 %) reached peak height velocity before their genitalia were in Stage 4 and over 20% did not do so until their genitalia were adult. Peak height velocity is reached, on the average, nearly 2 years later in boys than in girls, but the boys' genitalia begin to develop only about 6 months later than the girls' breasts. Pubic hair appears about 14 years later in boys than in girls.In a recent paper we described variations in the ages at which girls reached different stages of puberty and in the rates at which they passed from one stage of development to the next (Marshall and Tanner, 1969). We discussed also the degree to which progress in one event of puberty, for example breast development, could normally be out of step with another, such as growth of pubic hair. We now report a similar study of the maturation of boys.The ages at which Dutch boys reached various stages of genital and pubic hair development in 1965 were estimated in a large cross-sectional study by Van Wieringen et al. (1968), but there are no comparable recent data from other parts of Europe. In any case, cross-sectional data cannot tell us how much individuals vary in the rate at which they pass through puberty nor how the

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The health of a population is most accurately reflected in the rate of growth of its children. It is this theme which underlies the analysis and presentation of what is by far the largest compilation of growth data ever assembled. The first edition, published in 1976, included all known reliable recent results on height, weight, skinfolds and other body measurements from all parts of the globe. In this edition, the very numerous measurements taken between 1976 and 1988 have been included as well as the results of the large number of new studies made on rate of maturation as evinced by bone age and pubertal development stages. Many sections of the book dwell on disentangling the effects of the environment and heredity on growth, and thus answer the question of whether one universal standard suffices for all peoples of the world, or whether different populations (such as races or nations) should each have their own optimal growth standards. Written by practical people with experience of the problems in developing countries, this book explains in simple terms the different sorts of growth surveys, how to set about making them, and which sort to choose. All who are professionally concerned with child health should read it.

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