There is no cure, but there have been significant ad-
vances in life expectancy and treatment.
See also: GENOTYPE
Bibliography
Conyard, Shirley, Muthuswamy Krishnamurthy, and Harvey Dosik.
‘‘Psychological Aspects of Sickle-Cell Anemia in Adolescents.’’
Health and Social Work vol. 5 (1980):20–26.
DeRoin, Dee Ann. ‘‘Sickle Cell Anemia.’’ Written for Clinical Refer-
ence Systems, 1998, on NBCi [web site]. Available from http://
br.nbci.com/lmoid/resource/0,566,-2770,00.html; INTER-
NET.
National Library of Medicine. ‘‘Sickle Cell Disease in Newborns
and Infants: A Guide for Parents.’’ In the Wellness Web [web
site], 2001. Available from http://wellweb.com/index/
qsickle.htm; INTERNET.
Kathryn S. Lemery
SIGN LANGUAGE
Sign languages are the principal means of communi-
cation among members of deaf communities, with
most countries having their own distinct sign lan-
guage. In the United States, American Sign Language
(ASL) is the language typically used by persons who
have grown up deaf. Sign languages have gained con-
siderable attention outside of deaf communities
through the use of signs to foster communication in
minimally verbal hearing persons (e.g., children with
autism) and with nonhuman primates.
For centuries, sign languages were viewed as pri-
marily pantomimic—not true languages at all. This
belief helped support the oral approach to deaf edu-
cation, a strategy that eschewed signing and focused
on speech. Oralists advised parents of deaf children
to shun all forms of manual communication and to
promote spoken language acquisition through
speech training, hearing amplification, speech read-
ing, and writing. Sadly, many young people failed to
attain sufficient speech mastery through this ap-
proach. As a result, many schools for deaf students
today embrace a total communication approach. In
this approach, all avenues of communication, includ-
ing signing, are used to foster deaf students’ language
skills.
The pioneering research of William Stokoe
(1919–2000) did much to alter the view that sign lan-
guages were not true languages. Stokoe identified
three aspects of sign formation that distinguish one
ASL sign from another: the place where the sign is
made, the configuration and orientation of the hands,
and the hand and arm movement forming the sign.
These sign formational aspects function in a manner
similar to that of phonemes in spoken languages.
Subsequent studies demonstrated that ASL not only
has an extensive lexicon but it also operates as a rule-
governed, grammatical system. Most linguists now
recognize ASL and other sign languages used in deaf
communities as full and genuine languages.See also: AMERICAN SIGN LANGUAGE; HEARING LOSS
AND DEAFNESSBibliography
Bonvillian, John D. ‘‘Sign Language Development.’’ In Martyn
Barrett ed., The Development of Language. East Sussex, Eng.:
Psychology Press, 1999.
Klima, Edward S., and Ursula Bellugi. The Signs of Language. Cam-
bridge, MA: Harvard University Press, 1979.
Wilbur, Ronnie B. American Sign Language: Linguistic and Applied Di-
mensions, 2nd edition. Boston: College-Hill Press, 1987.
John D. BonvillianSINGLE-PARENT FAMILIES
Although the term ‘‘single-parent family’’ is a familiar
one, upon careful examination, the precise definition
of a single-parent family becomes less clear. Families
are frequently (although not exclusively) identified
on the basis of shared residential space and the pres-
ence of emotional bonds and support relationships
among members. ‘‘Single parent’’ implies that a solo
mother or father is responsible for the care of one or
more children under the age of eighteen within such
a family. For the purposes of this article, single-
parent families will be defined according to these
guidelines.
Such a definition, however, oversimplifies the di-
versity of circumstances that may define the lives of
single-parent families. For example, single parents
are usually fathers or mothers, but they are sometimes
single grandparents raising grandchildren. Single
parents may represent any of a variety of sexual orien-
tations. They may be biological, adoptive, or foster
parents. They may have arrived at their current life
circumstances through divorce, separation, or death
of a spouse, or may never have married at all. They
may have become single parents during adolescence
(often because of an unplanned pregnancy) or in
early or middle adulthood (because of an unplanned
pregnancy, through a deliberate decision to become
a single parent, or because of a divorce, separation,
or death of a spouse). In many cases, families classi-
fied as single parent by researchers or census takers
actually involve a committed residential coparenting
relationship, but one that is not legally recognized.
Finally, many families progress through a variety of
family structures over time (e.g., outside-of-marriage
adolescent single parenthood, followed by marriage
and subsequent postdivorce single parenthood). This
diversity and fluidity among single-parent families is366 SIGN LANGUAGE