ABSTRACT
Age, like race and gender, is based on a physical fact: an individual really has lived for a certain number of years and attained a certain level of physical maturation. The other system is the “generation” system, consisting of a set of age cohorts, each individual assigned permanently to one on the basis of when s/he and the cohort were born. A society’s age structure will also vary over time, as a large generation moves through the system or when a large or small next generation is born. One of the first issues to consider is the division and labeling of the life span. In American English, the typical life span is roughly subdivided into named phases like “infancy,” “childhood,” “adolescence,” “adulthood,” “middle age,” and so on. The concept or category of “childhood” has been subjected to extensive historical and cultural analysis. Adolescence has been a particularly controversial age-category and life-stage.
