The age at which puberty starts is something that
many children worry about. The onset of puberty
varies from child to child and is influenced by a
number of factors, including heredity, but it
generally begins between the ages of eight and
thirteen in a girl, and between ten and fifteen in a
boy. One of the factors that influences the onset of
puberty is nutrition. ---- Thus, the average age when
puberty started went down by well over a year. In
today’s developed world, malnutrition is rare and as
a result, over the last 50 years or so, there seems to
be a continuing trend toward an even lower average
age of puberty.