The earlier development of the female as compared with the male at the time of puberty is a constant phenomenon, to be observed in all races, in every climate, and in all strata of society. According to the statistical data published by the authors just quoted, the age of greatest development in the respective sexes is:
As regards weight at the age of 12 to 14 years. 14 to 17 years. As regards height at the age of 12 to 13 years. 12 to 15 years. As regards respiratory capacity at the age of 12 to 15 years. 15 to 17 years. As regards muscular strength at the age of 12 to 14 years. 14 to 15 years.
Puberty occurs in the female on the average about two years earlier than in the male, and upon this difference the observed differences in growth also depend.
The menarche in the wider signification of the term includes the development which occurs at the time of puberty, and continues through a period of several months, and even years, before complete sexual maturity is attained; and includes also the time, which may be considerable, following the first appearance of the menses and before the regular rhythm of the menstrual function is established and the full development of the female genital organs is attained. This time, which forms a notable phase of the sexual life of woman, is characterized by great changes in the genital organs and in the vital processes connected therewith, by a strong tendency to suffer from a series of very various pathological changes and disorders of function in the principal organs, and a lessened general resisting power to disease—a change which finds its most definite expression in the well-established fact that in this period of life the mortality among females is much greater than among males of corresponding age. According to the statistical data of _Quetelet_ and _Smits_, from the age of 14 to the age of 18 (the period of the menarche) there are 128 deaths of females for every 100 deaths of males; and even in the four succeeding years, from the age of 18 to the age of 22, the unfavorable conditions peculiar to sex are witnessed by 105 deaths of females to every 100 deaths of males.
Many authors draw a distinction between the age of puberty (from the Latin _pubes_, _puberis_), when the growth of the pubic hair occurs as an external sign of sexual development, and the age of nubility (from the Latin _nubere_), when the individual becomes fitted for marriage. The distinction is a partial one only, inasmuch as capacity for copulation is attained already at puberty. The law, however, maintains such a distinction, the Austrian Penal Code, for example, regarding intercourse with a female less than fourteen years old as rape, and the German Code likewise punishing carnal knowledge of a girl under fourteen.