Gender Identity Disorders
The Comprehensive Textbook of Psychiatry, Seventh Edition 2000
Kaplan, Sadock
Gender Identity Disorders
Richard Green, M.D., J.D. and Ray Blanchard, Ph.D.
[Abstract] Full Text [PDF]
ETIOLOGY
Much empirical evidence suggests that the three
main types of nonhomosexual gender identity disorder in males (heterosexual, bi
sexual, and asexual) are superficially variant forms of the same condition; that
nonhomosexual and homosexual gender identity disorder are etiologically
different conditions; that nonhomosexual gender identity disorder is
etiologically related to transvestic fetishism; and that homosexual gender
identity disorder is etiologically related to typical homosexuality.
The conclusion that heterosexual, bisexual, and asexual gender identity
disorders are superficially variant forms of the same condition is based on a
wide variety of evidence. Similar majorities of men with heterosexual, bisexual,
and asexual gender identity disorder acknowledge some history of transvestic
fetishism; such self-reports are rare in men with homosexual gender identity
disorder. Men with heterosexual, bisexual, and asexual gender identity disorder
are also similar to each other, and dissimilar to men with homosexual gender
identity disorder with regard to their degree of recalled childhood femininity,
age at clinical presentation, extent of interpersonal heterosexual experience,
and a history of erotic arousal in association with thoughts of being a woman.
It is possible that the common denominator linking transvestic fetishism and
heterosexual, bisexual, and asexual gender identity disorder is autogynephilia,
a male's tendency to be sexually aroused by the thought or image of himself as a
woman. Autogynephilia is highly variable in its manifestations. It may be
expressed in fantasies of dressing as a woman (transvestic fetishism); in
(masturbatory) fantasies of engaging in stereotypically feminine behavior like
knitting; in fantasies of gestating, lactating, or menstruating; in fantasies of
being treated by other people as a woman; or in fantasies of possessing a
woman's body. When an autogynephilic man's favorite sexual fantasy is that of
possessing a vagina, he is very likely to develop cross-gender wishes that
persist even when he is not sexually aroused, along with a desire for surgical
sex reassignment.
Autogynephilia may be conceived as a modified form of heterosexuality, in which
a man's sexual approaches are directed not at external women but at a feminized
version of himself. It seems to involve some developmental anomaly in the
learning of sexual behavior, because the man's principal erotic object in many
cases-for example, the thought or image of himself wearing pantyhose, applying
make-up, or knitting-cannot be innate but must have been assembled from
experiences. It remains to be discovered whether some men are relatively prone
to such developmental anomalies for neurological reasons.
The conclusion that homosexual gender identity
disorder and typical homosexuality (i.e., homosexuality without gender identity
disorder) have etiological commonalities is based on two lines of evidence. The
first is that the early manifestations and homosexual gender identity disorder
appear rather similar. Research has consistently shown that at least 50 percent
of asexual men with no gender identity problems nonetheless recall significant
amounts of cross-gender behavior in childhood. Similar although somewhat less
striking findings obtain for homosexual women. These observations suggest that
the difference between ordinary homosexuality and homosexual gender identity
disorder begin as a difference in degree, which develops during adolescence into
a difference in kind, when the less severely affected children shed their
cross-gender traits and the more severely affected children elaborate them into
a full-blown cross-gender identity. The second line of evidence is
epidemiological in nature and pertains only to males. Research on homosexual men
without gender identity disorders has established that homosexual men are on
average born later in the sibling order than comparable heterosexual men. Recent
studies have established that this difference in birth order is caused by
homosexual males having a greater number of older brothers; they do not have a
greater number of older sisters, once their number of older brothers has been
taken into account. Studies of Dutch, Canadian, and British male patients with
gender identity disorder have produced the similar finding that homosexual
patients are on average born later than nonhomosexual patients. These
observations suggest that whatever etiological factor is reflected by high
birth order contributes to the development both of homosexuality and of
homosexual gender identity disorder.
The foregoing discussion illustrates that
theories developed to explain homosexuality or transvestic fetishism may also
apply to homosexual or nonhomosexual gender identity disorder respectively.
Furthermore, theories developed to explain gender identity disorder without
further qualification may apply to only one of the two main types.
BIOLOGICAL FACTORS
Theories of homosexual development, notably in
males, have taken on an increasingly biological basis as opposed to an
experiential one.
Genetic Factors
The Franz Kallmann twin study of the 1950s
found a 100 percent concordance for homosexuality between presumably monozygotic
male twins. Further research indicated discordant pairs, and methodological
critiques of the Kallman study resulted in a general decline of interest in the
genetic basis. However, in recent years twin studies and other family studies of
sexual orientation have promoted new interest. A 1991 study of 56 male
monozygotic pairs of twins raised together found a 52 percent concordance for
homosexuality compared with 22 percent for 54 dizygotic pairs. A 1992 study
found that of 71 female monozygotic twin pairs, 48 percent were concordant for
homosexuality or bisexuality compared with 16 percent for 37 dizygotic pairs.
Monozygotic twins separated at birth, although rare, provide a better model for
testing the relative influences of environment and genetics than do twins reared
together, where the two factors are confounded. A report of two pairs of males
separated at birth argues for an inherited influence on homosexual orientation.
In one pair, both men were homosexually oriented. In the second pair, one twin
was homosexual, and the other, while heterosexually married, had had a 3-year
homosexual relationship in adolescence. By contrast, in four pairs of separated
female-female twins where one twin in each pair was lesbian, none of the cotwins
was lesbian.
Family studies of nontwin siblings of
homosexual men and women also lend support to a genetic basis, although the
confound of a similar environment is considerable. Two studies found higher
rates of homosexuality in brothers than is expected in the general male
population. No corresponding increase in the number of lesbian siblings was
reported. Two gene linkage studies add further weight to a genetic basis of male
homosexuality. When families are selected for having male homosexuals on the
mother's side of the family tree, and two of the mother's sons are homosexual,
there is an increased probability of a marker for a shared gene on the sons' X
chromosome (contributed by the mother). The marker is less often shared between
a homosexual and a heterosexual brother.
Hormonal Factors
Evidence for a hormonal influence on gender
identity disorder derives from several research sources. One possible source is
congenital virilizing adrenal hyperplasia. Girls with this condition overproduce
adrenal androgen from before birth. They are more rough-and-tumble, less
interested in doll play, and likely to be considered tomboys than girls without
the condition. Conversely, there is limited evidence that prenatal exposure of
males to estrogenic or progestational agents may reduce the expression of
conventional boy-type behaviors. Atypical levels of sex-typed hormones before
birth and the attendant effects on specific sex-typed behaviors can
substantially modify the child's early social experiences. Boys who are
disinclined to rough-and-tumble play or who play with dolls have different
father-son and mother-son relationships and a different peer group experience
from more conventionally masculine boys.
Similarly, girls who prefer rough-and-tumble
activity and sports to doll play have a different early socialization experience
with parents and peers from girls who are conventionally feminine. Thus,
hormonal influences may act through a pathway of affecting sex-typed behaviours
that interact with socialization experiences. Reported neuroendocrine and
neuroanatomical differences also suggest an inborn contribution to sexual
orientation, particularly in men. One phenomenon tested is the feedback response
on luteinizing hormone (LH) after an intravenous pulse of estradiol. In women
there is a marked rebound after an initial drop (the hormonal basis of
ovulation). The original research found an attenuated female-like response in
homosexual men, which theoretically reflected a deficiency in prenatal
androgenization of the central nervous system (CNS). In another study using the
same methodology, more than a sample of homosexual men showed a response more
like that of the heterosexual women than of the heterosexual men in the study.
However, a subsequent study, which used a
different approach to elicit the luteinizing hormone feedback phenomenon, found
no significant group difference, and another study with a methodology similar to
that used in the original research also failed to confirm a difference. A
related phenomenon that suggests that a deficiency in male in utero leads to a
homosexual orientation in men derives from the prenatal stress theory.
Stressing pregnant rodents results in feminized
behavior in male offspring, owing either to the competition between adrenal
stress steroids and testicular androgens or to the mistiming of testicular
androgen secretion as a result of stress. In one study a higher-than-average
rate of homosexuality was found in men who were born in Germany between 1941 and
1946, the stressful years of World War II. However, an environmental explanation
is also possible, because fathers were more likely to be away from their sons
during the war.
A second study, based on retrospective reports
by homosexual, bisexual, and heterosexual men describing stress in their
mothers, found more stress during the pregnancies of the mothers of homosexual
men. Other research has been less supportive of an association between stress
and homosexuality. Some research found no connection. One American study found a
marginally significant relationship, based on the reports of mothers of college
students. Another found a low correlation between reported pregnancy stress and
lesbianism, but not with male homosexuality. No prospective studies are
reported. Although medical histories given by parents of children with gender
identity disorder do not provide a basis for grossly abnormal hormone levels
before birth, a neuroendocrine base may still be posited at a more subtle level.
If the range of prenatal androgen levels is as wide as that in adult life, the
fetus may also be exposed to a wide range of androgen. Another factor could be
the androgen surge that occurs in boys between about 3 weeks and 3 months of
age.
Immunological Theories
Two immunological theories have been advanced
to explain the finding that homosexual men (including those with gender
dysphoria of the homosexual subtype) have a greater average number of older
brothers than do heterosexual men. Both theories propose that male homosexuality
may result from a maternal immune reaction, which is provoked only by male
fetuses and which becomes stronger after each pregnancy with a male fetus. The
earlier theory proposed that antibodies to testosterone, produced by a woman
pregnant with a male fetus and passed through the placenta from the mother to
the fetus, could reduce the hormone's biological activity and thus compromise
the sexual differentiation of the fetal brain. This seems unlikely because
steroid hormones are not ordinarily antigenic. An alternative theory is that the
relevant fetal antigen might be one of the male-specific, Y-linked, minor
histocompatibility antigens, often referred to collectively as H-Y antigen.
Although there is no direct evidence for this theory, it is consistent with a
variety of observations, including the finding that male mice whose mothers were
immunized to H-Y prior to pregnancy are much less likely to mate successfully
with receptive females.
Brain and CNS Involvement
A difference in a nucleus of the anterior
hypothalamus may represent a CNS difference related to sexual orientation. The
area known as interstitial nucleus of the anterior hypothalamus-3 (INAH-3) was
compared in autopsy between homosexual men, heterosexual men, and heterosexual
women. Although there was some overlap between the size of the nucleus between
the groups, it was smaller on average in the homosexual men and women compared
with the heterosexual men. All the homosexual men and some of the heterosexual
men and women had died of acquired immune deficiency syndrome (AIDS), but death
from AIDS was not a factor. No homosexual women were studied to determine
whether the size of their nucleus was similar to that of the heterosexual men.
INAH-3 is embedded in the hypothalamic area that appears to be related to some
aspects of sexual behavior in male nonhuman primates.
This study has neither been confirmed nor
refuted by subsequent research. Another finding, of a larger suprachiasmatic
nucleus in a sample of homosexual men, may be less relevant because that area is
not known to be associated with sexual behavior. However, it may be related to
endocrine function. A more recent finding points to a difference in the brain of
male-to-female transsexuals. In a post mortem sample of 6, the bed nucleus
corresponded in size to that of typical females rather than to that of typical
males; it was not relevant whether the male transsexual was heterosexual or
homosexual.
Psychosocial Theories
Psychodynamic and behavioral influences may
lead to extensive cross-gender identification. In an early study boys with an
excessive mother-son symbiosis in the early years, replete with extensive
mother-son skin-to-skin contact, appeared later to manifest significant feminine
behavior. This is attributed to the inability to differentiate psychologically
from the mother. Male- identified females have been reported to have mothers who
were removed in affect from their children, frequently by depression, and
fathers who did not support their daughters' femininity. The girl becomes a
substitute husband to treat the mother.
Other reports describe traumatic psychological
losses to boys and girls in the earliest years that appear related to the onset
of cross-gender behavior. Research on a sample of 66 boys with gender identity
disorder found a positive correlation between the extent to which parents
supported cross-gender behaviors in their sons and the extent of that
cross-gender behavior. In most of the families at least initially there was no
discouragement of cross-gender behaviors.
In more limited work with girls with gender
identity disorder, initial parental reactions were similar. A study of
cross-gendered boys found the extent of father-son involvement in the early
years to be related to later sexual orientation. The association emerged not
only between the two groups of boys studied (gender identity disorder and
control) but within the subgroup of boys with gender identity disorder. Less
father-son involvement was associated with a more homosexual orientation.
Social Learning Theories
Social learning theories typically focus on the
differential reinforcement by parents of sex-typed behaviors, starting shortly
after
birth. This reinforcement shapes conduct into conventional masculinity or
femininity. Cause and effect are hard to distinguish here. On the one hand, sex
differences are reported early in life, probably before any major differential
impact of parental reinforcement; on the other hand, mothers and fathers
apparently treat male and female newborns differently.
In Baby X experiments adults are told,
sometimes incorrectly, the sex of a clothed child and asked to describe the
child's attributes or to provide it with toys. Perceived boys are encouraged
more to physical action and are given more whole-body stimulation than perceived
girls. When 6-month-old children were similarly clothed, toy choice by adults
was related to perceived gender of the child. Boys were presented with
footballs, girls with dolls. Strong bald babies were seen as male, soft fragile
ones as female. At 1 year, boys may be more exploratory and active and toy
preferences may differ. Girls were found to prefer soft toys and dolls whereas
boys preferred transportation toys and robots. A preference for same-sex
playmates emerges early. When 31/2- to 41/2-year-olds were shown photographs of
boys and girls and asked to select those with whom they would like to play, boys
preferred boys and girls preferred girls. By age 2 to 3 years, boys appear to be
more aggressive toward peers and to show more rough-and-tumble play. Fathers are
as likely to give a 1-year-old daughter a truck as a doll but more likely to
give the son a truck. However, when children are given dolls, boys play with
them less than girls. Fathers more than mothers give negative responses to boys
playing with dolls. Boys receive more positive responses for playing with blocks
and girls receive more positive responses for playing with dolls.
Imitative and vicarious learning pervade
general theories of social learning of sex typing. In imitative learning,
behaviors are adopted that simulate those of a significant other person, the
model. In vicarious learning, if something happens to a model the viewer's
behavior is modified to resemble the model because the child perceives the model
as possessing desirable attributes or obtaining desirable goals. The cognitive
developmental theory, by contrast, sees the child first labeling itself as male
or female and then finding the behaviors associated with that label rewarding.
Nature Versus Nurture
The classic research on intersexed or
hermaphroditic children pointed to the early-life emergences of gender identity
as being influenced primarily by environment and as irreversible. In the studies
by John Money, Joan Hampson, and John Hampson, a range of anatomical features
discordant with the gender of rearing were found to be less relevant to the
adoption of a male or female gender identity than the gender of rearing.
Studies of matched pairs, for example,
demonstrate that with the syndrome of congenital virilizing adrenal hyperplasia,
the newborn female, if considered to be male and designated male, matures with a
male identity in spite of having the XX female chromosomal pattern, ovaries, and
a uterus. If considered female the child matures with a female identity.
However, questions have been raised about the generalizability of those findings
to nonintersexed children because of the atypical prenatal endocrine environment
and other atypical genetic or anatomical influences of intersexed children.
Studies of children born with normal sex
characteristics who undergo gender reassignment early in life may be a more
relevant test of nature versus nurture. The tragedy of penile amputation,
usually through negligent circumcision, has provided such a model. In one
celebrated case a reassigned male monozygotic twin who was reportedly being
raised successfully as a girl failed to incorporate a female identity and now
lives as a heterosexual male. Reassignment in that case was at 22 months, which
may have been after core identity as a male was in place.
A somewhat more complicated outcome was
revealed in the very recent psychosexual follow-up of another biologically
normal male whose penis was accidentally ablated during circumcision at the age
of 2 months. The decision to reassign as a female occurred sometime between 2
and 7 months, at which point surgical castration occurred. At age 26 years,
clinical interviews and self-report questionnaires were used to obtain
information on the patient's gender identity, gender role, sexual orientation,
and sexual identity. In adulthood the patient lived socially as a woman and her
gender identity was unequivocally female, with no evidence of gender dysphoria.
However, the patient's childhood gender role behavior had been predominantly
masculine, and her current
occupation was male-dominated. Moreover, she fantasized sexually about women
more often than about men. On the other hand, her objective sexual history
included roughly equal amounts of sexual experience with women and men. At the
last follow-up, the patient was living with a new female partner, in a lesbian
relationship.
Psychoanalytic Theories
As in other areas of pathology, psychoanalytic
theories about gender identity disorder constitute a tradition distinct from
biological and other nonbiological approaches. One influential theory is that of
Ethel Person and Lionel Ovesey, who advanced the hypothesis that transsexualism
in males originates from unresolved separation anxiety during the
separation-individuation phase of infantile development. To cope with this
anxiety, the child resorts to a reparative fantasy of symbiotic fusion with his
mother. Adult transsexualism may be understood as an attempt to master that
anxiety through sex reassignment surgery, through which the transsexual acts out
his unconscious fantasy and symbolically becomes his mother.
According to this hypothesis, male transsexuals
vary in the directness with which they proceed to the transsexual resolution.
Some individuals never develop any other psychosexual phenomena as defenses
against separation anxiety, and they proceed to the transsexual outcome in a
straightforward manner. Others develop transvestism or effeminate homosexuality
as initial defenses. When those defenses fail in the face of various stressors,
the individual regresses to the primitive fantasy of symbiotic fusion with his
mother and begins to experience transsexual impulses.
The other major psychoanalytic theory was
developed by Robert Stoller to explain the etiology of transsexualism in a
specific group of biological males, who would fall within the DSM-IV category of
gender identity disorder, sexually attracted to males. Stoller called those
males true transsexuals.
The theory begins with the grandmother of the
future transsexual who treats her daughter coldly and neither encourages nor
models femininity for her. The grandfather has a closer relationship with the
daughter, but he encourages masculinity in her. In consequence the mother of the
future transsexual develops a mild gender identity disorder of her own. In
adolescence, however, she abandons her conscious transsexual wishes of someday
being male and adopts a heterosexual façade. At the unconscious level she
nevertheless retains a strong penis envy. The transsexual's mother eventually
enters an empty and marriage with a passive and withdrawn husband who is
psychologically if not physically absent from the household. The final
pathogenic process becomes operative when the mother gives birth to an infant
son she perceives as particularly beautiful and graceful. The boy, who
represents her feminized phallus, fulfills her lifelong wish for a penis. The
mother-son interaction, described by Stoller as a blissful symbiosis, includes
excessively close and prolonged body contact, sometimes with the infant's nude
body cradled against the mother's nude body. The mother's behavior expresses her
need to treat her son an extension of her own body.
The transsexual's early experiences, especially
the continuous skin-to-skin contact, produce an overidentification with his
mother, a blurring of ego boundaries, and eventually a feminine gender identity.
The transsexual boy never develops a "heterosexual" relationship with
his mother and therefore never develops an oedipal conflict. His femininity is
produced nonconflictually and remains a nonconflictual, autonomous form of
behavior. This theory does not account for "secondary" transsexuals,
notably those who evolve through a transvestite, heterosexual pattern.
Citation:
Richard Green, M.D., J.D. and
Ray Blanchard, Ph.D.
