Page 222 - Environment: The Science Behind the Stories

include public health issues, such as people’s access to con- Worldwide in 2012, 56% of women (aged 15–49)
traceptives and the rate of infant mortality. They also include reported using contraceptives, with rates of use varying
cultural factors—such as the level of women’s rights, the rela- widely among nations. China, at 84%, had the highest rate
tive acceptance of contraceptive use, and even television pro- of contraceptive use of any nation. Eight European nations
grams (see The Science behind The STory, pp. 222–223). There showed rates of contraceptive use of 70% or more, as did
are also effects from economic factors, such as the society’s Australia, Brazil, Canada, Colombia, Costa Rica, Cuba,
level of affluence, the importance of child labor, and the avail- Dominican Republic, Micronesia, New Zealand, Paraguay,
ability of governmental support for retirees. Let’s now exam- Puerto Rico, South Korea, Thailand, the United States,
ine a few of these societal influences on fertility more closely. and Uruguay. At the other end of the spectrum, 14 African
nations had rates below 10%.
Family planning is a key approach Low usage rates for contraceptives in some societies are
for controlling population growth caused by limited availability, especially in rural areas. In oth-
ers, low usage may be due to religious doctrine or cultural
Perhaps the greatest single factor enabling a society to slow its influences that hinder family planning, denying counseling
population growth is the ability of women and couples to engage and contraceptives to people who might otherwise use them.
in family planning, the effort to plan the number and spacing This can result in family sizes that are larger than the parents
of one’s children. Family-planning programs and clinics offer desire and to elevated rates of population growth.
information and counseling to potential mothers and fathers on In a physiological sense, access to family planning (and
reproductive issues. An important component of family planning the civil rights to demand its use) gives women control over
is birth control, the effort to control the number of children a their reproductive window, the period of their life, beginning
woman bears by reducing the frequency of pregnancy. Birth con- with sexual maturity and ending with menopause, in which
trol relies on contraception, the deliberate attempt to prevent preg- they may become pregnant. A woman can bear up to 25 chil-
nancy despite engaging in sexual intercourse. Common methods dren within this window (Figure 8.17a), but she may choose
of modern contraception in use today include condoms, spermi- to delay the birth of her first child to pursue education and
cide, hormonal treatments (birth control pill/hormone injection), employment. She may also use contraception to delay her
intrauterine devices (IUDs), and permanent sterilization through first child, space births within the window, and “close” her
tubal ligation or vasectomy. Many family-planning organizations reproductive window after achieving her desired family size
aid clients by offering free or discounted contraceptives. (Figure 8.17b).

Reproductive window

First menstrual
cycle

Last menstrual
cycle (menopause)

Birth 10 years 20 years 30 years 40 years 50 years 60 years
(a) Potential fertility

Delaying childbirth to focus
on education and career
Spacing births with
contraception Ending reproductive
potential with
First menstrual contraception
cycle
Last menstrual CHAPTER 8 • Hum A n Po P ul AT i on
cycle (menopause)

Birth 10 years 20 years 30 years 40 years 50 years 60 years
(b) Fertility reductions by delaying childbirth and contraceptive use

Figure 8.17 Women can potentially have very high fertility within their “reproductive window” but
can choose to reduce the number of children they bear. They may do this by delaying the birth of their first
child, or by using contraception to space pregnancies or to end their reproductive window at the time of their
choosing. 221

M08_WITH7428_05_SE_C08.indd 221 12/12/14 2:58 PM