puberty marks the point in human development where both males and females gain the capability to procreate. Puberty occurs during
adolescence, which begins as early as age 10 and is usually completed by age 17. For girls, a rising level of
oestrogen (female hormone) sets the process in motion.
Pelvis and
breast development are followed by a spurt in height and then the growth of underarm and pubic hair. Finally,
menarche, the beginning of the first
menstrual cycle, occurs. Ovulation does not automatically coincide with menarche. It may take as many as forty cycles for ovulation to become a regular part of the menstrual cycle. Though they are uniform in order, the age of onset, pace, and duration of these changes vary widely from one individual to another. Since the beginning of the twentieth century, the average age of first menstruation has declined. In the US, it decreased from about 14 years old in 1900 to 12 years old in 1975. Scientists attribute this change to better living standards, particularly in regard to diet. In males a sharp increase in
androgen (male hormone) and
growth hormone spawns skeletal development, followed by the lowering of the voice, the growth of facial hair, increase in sex organ size, height, spermatogenesis, and muscle development. The outward physical signs of puberty tend to occur earlier in girls than in boys, particularly the growth spurt.
While the physiological terrain of puberty is clearly mapped, psychological and cultural changes meander in a much less orderly direction. Adolescence, by definition, begins in childhood and ends with young adulthood. To negotiate successfully this stage of human development, girls and boys must develop conceptual powers, independence, a sense a their own identity, and a way to make moral or ethical decisions. All the while, they are grappling with their emerging
sexuality, marked by heightened sexual development and sexual interest.
The ‘normal’ routes through puberty vary according to cultural standards, socio-economic class, gender roles, and family structure. Some cultures and religions have clearly established rituals to mark puberty. The Jewish bar mitzvah, for example, celebrates a boy's entry into adolescence, and most of tribal Africa holds puberty rituals which may include dance, music, or seclusion.
According to John and Virginia Demos, adolescence is a rather modern invention which ‘did not exist before the last two decades of the nineteenth century.’ Its invention resulted from an increased focus on children among the middle classes, who no longer needed their children's labour for family survival and so re-defined childhood and puberty in more psychological and social terms. In addition, the nineteenth-century research of social scientists such as G. Stanley Hall and Sigmund Freud emphasized distinct categorizations for each stage of human development. The influential Hall defined adolescence as stressful, violent, and crisis-ridden.
Margaret A. Lowe
Bibliography
John and and Virginia Demos (1973). Adolescence in historical perspective. In The American Family in Social-Historical Perspective. St Martin's Press, New York.
See also
development and growth: school age and adolescence;
sex hormones.
