28 Part One Children in Today’s World
may begin and end. Because this
book is about child development,
only the fi rst six stages (those that
involve children) are described
here. The life cycle also includes
stages for teens and adults.
The prenatal stage begins at
conception and ends about nine
months later at birth. The rate of
growth at this stage is the fastest
it will be in life. In this stage, a
child grows from a single cell to
a complete organism.
The neonatal stage extends from
birth through the second week.
During this period, the baby
physically adapts to life outside
the mother’s body.
The infancy stage begins at two
weeks and continues through
the fi rst birthday (12 months).
The infant develops the
foundation for motor, thinking,
language, and social skills.
The toddler stage begins
at 12 months and ends at
36 months (the child’s third
birthday). In the toddler stage,
the child makes great strides in
motor, thinking, and language
skills and begins to test his or
her dependence on adults.
The preschool stage begins at
three years and ends at the
sixth birthday. During this
stage, the child becomes more
self-suffi cient, spends many
hours in play exploring the
physical and social world,
and develops a rather stable
self-concept.
The school-age stage, or middle
childhood, begins at 6 years
and ends at 12 years. This stage
corresponds to the typical ages of
children in the elementary school
years. Achievement is the central
goal of these years. School-age
children master the basics of
reading, writing, and arithmetic.
They are exposed to many
other learning opportunities,
too. In school, children interact
with peers more and learn by
group instruction. This makes
it important for them to learn
self-control.
Factors That
Influence Growth
and Development
Why is each child different?
Two main factors infl uence growth
and development. First, each child
has unique, inborn traits. Heredity
includes all the traits that are passed to
a child from blood relatives. Second,
a child’s surroundings also play a
large role. Environment includes all
the conditions and situations that
surround and affect a child.
The way these two factors
combine also makes children different
from one another. Experts are
studying how these two factors affect
children’s growth and development.
They continue to learn, but
unanswered questions remain.
Heredity
You have many traits in common
with all the other members of your
family. These traits pass to you in
complex ways through your parents’
genes at the moment of conception.
Genes are sections of the DNA
molecule found in a person’s cells
that determine the individual traits
,