Comparison of growth rates and menarcheal age for groups of boys and girls, ages 6 to 15, in Tokyo (Japan) found that children with mental retardation had a smaller growth spurt during puberty but did not differ in maturational rate defined by age at pubertal height spurt or age at menarche. (Author/DB)

Presents statistics of a girl's age, height, and weight at menarche, and the possible effect on these variables of various factors such as her health, genetic inheritance, socioeconomic circumstances, and environment. The behavior of present day adolescents cannot be attributed to earlier physical and sexual development. (Author/IRT)

The study reported in this book provides descriptive material about a national sample of illegitimate children born in Great Britain in 1958. It compares their development with legitimate children who were born in the same week as they were, and it relates their development, at the age of seven years, to a range of factors linked with their birth…