Adolescence is a fluid
concept: the traditional age-bound defi nition of this
phase of life (10–19 years)1
is greatly infl uenced by social,
environmental, and cultural factors. Puberty is
considered by many as signifying the onset of
adolescence and this is often associated, in girls, with
menarche; as the age of menarche fell, particularly in
the early part of the last century in developed countries,2
the onset of adolescence also seemed to take place at a
younger age. In many cultures, for example in the
Hmong culture of southeast Asia, the age of 12 or
13 years denotes the end of childhood and the
simultaneous onset of adulthood.3
In Bangladesh, a
child who goes to school and has no economic or social