|
Adolescence is commonly defined as the interval between the onset of puberty and the transition to adult roles (Steinberg et al., in press). The temporal borders of this developmental period are not precise. At the lower boundary, the onset of puberty involves a series of overlapping physiological changes, including a rise in hormones, the onset of menstruation for females, and the maturation of the ovaries or gonads. These changes may begin as early as ages 6 to 8 and may not end until ages 15 to 17 (McClintock and Herdt 1996). However, on average, menstruation begins at approximately 12–13 years of age in industrialized nations and later in nations plagued with malnutrition and disease (Eveleth and Tanner 1990; Herman-Giddens et al. 1997). The age at which youths reach the upper boundary of adolescence and take on adult’s roles, such as self-supporter, spouse, and parent, also varies considerably across people and cultures.
|
