Understanding Psychology (10th Ed)

2. Specifi c kinds of growth must take place during a 
period if the embryo is to develop normally.
3. A 
is an environmental agent such as a drug, 
chemical, virus, or other factor that produces a birth defect.
R E T H I N K
1. Given the possible effects of the environment on a 
developing fetus, do you think pregnant women should 
be prosecuted for the use of alcohol and other drugs that 
may do serious harm to their unborn children? Defend 
your position.
2. From the perspective of an educator: How would you 
utilize your knowledge of sensitive periods in language 
development to improve students’ learning? Would you 
want to teach children more than one language during 
this time?
Answers to Evaluate Questions 
1. 1-b, 2-a, 3-c; 
2.
critical; 3.
teratogen
K E Y T E R M S 
chromosomes p. 386
genes p. 386
zygote p. 388
embryo p. 388
fetus p. 388
age of viability p. 388
teratogens p. 390
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His head was molded into a long melon shape and came to a point at the back . . . . He 
was covered with a thick greasy white material known as “vernix,” which made him 
slippery to hold and also allowed him to slip easily through the birth canal. In addition 
to a shock of black hair on his head, his body was covered with dark, fi ne hair known 
as “lanugo.” His ears, his back, his shoulders, and even his cheeks were furry . . . . His 
skin was wrinkled and quite loose, ready to scale in creased places such as his feet and 
hands . . . . His ears were pressed to his head in unusual positions—one ear was 
matted fi rmly forward on his cheek. His nose was fl attened and pushed to one side by 
the squeeze as he came through the pelvis. (Brazelton, 1969, p. 3) 
What kind of creature is this? Although the description hardly fi ts that of the ador-
able babies seen in advertisements for baby food, we are in fact talking about a 
normal, completely developed child just after the moment of birth. Called a  neonate, 
a newborn arrives in the world in a form that hardly meets the standards of beauty 
against which we typically measure babies. Yet ask any parents: Nothing is more 
beautiful or exciting than the fi rst glimpse of their newborn.
The Extraordinary Newborn
Several factors cause a neonate’s strange appearance. The trip through the mother’s 
birth canal may have squeezed the incompletely formed bones of the skull together 
and squashed the nose into the head. The skin secretes vernix, a white greasy cover-
ing, for protection before birth, and the baby may have lanugo, a soft fuzz, over the 
entire body for a similar purpose. The infant’s eyelids may be puffy with an accu-
mulation of fl uids because of the upside-down position during birth. 
All these features change during the fi rst two weeks of life 
as the neonate takes on a more familiar appearance. Even 
more impressive are the capabilities a neonate begins to dis-
play from the moment of birth—capabilities that grow at an 
astounding rate over the ensuing months.