STUDENT CASE STUDY—BAUER
THE TWO-SEX SYSTEM: FACT OR FALLACY?
CASE STUDY FOR AAC&U STIRS PROJECT
Angela Bauer, Professor and Chair of Biology, High Point University, High Point, NC
STUDENT CASE
Introduction
Perhaps no other method of categorization permeates our culture so thoroughly as
that of classifying according to sex (biological characteristics we associate with being
male or female) and/or gender (social behaviors we associate with being masculine vs.
feminine). The desire to categorize in this regard is so compelling, that typically the
first words out of a person’s mouth upon hearing about the birth of a child are, “Is it a
boy or a girl?” Likewise, the desire to categorize as male vs. female or masculine vs.
feminine is far-reaching; names, hairstyles, clothing, bathrooms, athletic events, even
shampoos—all are categorized within the context of the binary male/female
framework.
Yet is this binary view of sex and gender accurate? Does it reflect what exists within
the natural world? Can everyone be placed into one of two “boxes” (male or female)
with respect to their sex and gender? And why is the impulse to categorize in this
regard so strong? While it is true that at times our culture and media attempt to
celebrate the concept of androgyny, most people admit to reacting with discomfort
when faced with an individual or situation that defies categorization by the sex/
gender binary. Consider the case of female athlete Caster Semenya, whose sex was
investigated following her gold medal win in the 800-meter dash of the 2009 World
Championship:
“In August 2009, Caster Semenya, a young South African runner, won the
women’s 800-meter race at the Berlin World Championships in Athletics
by a margin of 2.45 seconds and immediately found herself at the center
of international controversy amid a frenzy of speculation about whether
she was ‘really’ a woman (Clarey 2009). The controversy was sparked by
complaints from Semenya’s competitors; they pointed not to the large
margin of her win, but to what one writer referred to as her
‘breathtakingly butch’ appearance (Levy 2009), remarking, ‘Just look at
her’ and ‘These kinds of people should not run with us . . . For me, she is
not a woman. She is a man’ (Adams 2009; Levy 2009). Shortly after the
media reported these comments, a supposedly misdirected fax notified
the press that the IAAF had actually required Semenya to undergo ‘sex
testing’ shortly before her Berlin win (Levy 2009). The IAAF had ordered
South African authorities to perform the tests after Semenya broke a
national junior record at the African championships in Mauritius.
Throughout the testing, Semenya had been under the impression she was
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STUDENT CASE STUDY—BAUER
undergoing standard doping tests owing to her win (BBC 2009).
In a moment when she might have been celebrating her victory, Semenya
endured a cruel and humiliating media spectacle; sports commentators
ridiculed her appearance, called her names including ‘hermaphrodite,’
and cried out for her medal and prize money to be returned (Levy 2009;
A.D. Smith 2009). Under a typical headline, Time.com trumpeted ‘Could
This Women’s World Champ Be a Man?’ (Adams 2009). Semenya was
reportedly subjected to a two-hour examination during which doctors put
her legs in stirrups and photographed her genitalia (Levy 2009; A.D. Smith
2009). Afterward Semenya sent distraught messages to friends and family
(Levy 2009; A.D. Smith 2009). Test results purportedly indicated that
Semenya had an intersex condition that left her without a uterus or
ovaries and with undescended testes producing androgens at three times
the typical level for females (known as hyperandrogenism) (Hurst 2009).
[Note that Semenya’s elevated androgen levels did not confer to her any
athletic advantage, due to the fact that she lacks androgen receptors to
mediate the hormone’s effects.] After these intensely intimate details
about Semenya’s body became a topic for public debate and scrutiny, she
went into hiding; she reportedly required trauma counseling in the wake
of claims that sex tests confirmed she was a ‘hermaphrodite’ (Levy 2009;
A. D. Smith 2009).
The IAAF banned her from competitions while it completed its
investigation. Eventually, after an 11-month investigation—a process that
involved 10 months of negotiation with the IAAF involving legal
representatives and a high-profile mediator known for his work on
international disputes—the IAAF cleared Semenya for competition and
her Berlin victory was allowed to stand (Dewey and LeBoeuf 2010).”
[Excerpt taken from Karzakis et al. 2014]
Of note regarding Semenya’s story is the fixation of her fellow athletes, the media,
and the public on her androgynous appearance (more so than on any athletic
advantage her intersex condition may have conferred; Karzakis et al. 2014). Significant
discomfort (in some cases, ridicule) was elicited by her appearance, which didn’t fit
neatly within the sex/gender binary. There existed so much discomfort in this regard
that Semenya was actually pressured into having significant medical procedures
performed to “feminize” her appearance, including surgery to reduce the size of her
clitoris. Clitoral reduction surgery is a risky and complicated medical procedure,
conducted for the sake of feminizing appearance. Furthermore, the surgery can cause
scarring, pain, and numbness in the vulva, resulting in long-term impairment of one’s
sexual response (Crouch et al. 2007; Piaggio 2014). In short, it is a surgery that is
performed for the benefit of upholding the sex/gender binary, and not for the sexual
health of the individual. And yet it is still a surgery that is widely used within the
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STUDENT CASE STUDY—BAUER
medical community to “treat” intersex individuals like Semenya (Fausto-Sterling 2000;
Romao et al. 2012; Piaggio 2014).
In this case study, you will engage in readings and activities that encourage you to
consider the validity of society’s two-sex system. In addition to learning about the
biologic factors that contribute to sexual phenotype (male, female, intersex), you will
examine data sets that illustrate the significant variability in expression of secondary
sex characteristics that exists within the natural world. You will consider the role that
scientific texts have played in perpetuating the formation of the sex/gender binary.
Finally, you will engage in debates with your peers, during which you will formulate
arguments that are either in favor of or against the application of binary views and
language pertaining to sex and gender on college campuses, particularly when making
decisions pertaining to campus housing.
Specific learning objectives for the case study—as well as the activities and
assignments included to address each objective—include:
Learning Objective
1. To explain the biology of sexual
development and the contributions of six
key factors—chromosomes, gonads,
hormones, external genitalia, internal
genitalia, and secondary sex characteristics
—to sexual phenotype
2. To explain the causes of intersex
conditions, their prevalence within the
human population, and common approaches
used within the medical community to
“treat” them
3. To analyze and interpret data sets
illustrating variability in expression of
common secondary sex characteristics
Related Activities/Assignments
Unit One
 Reading assignment: “The Biology of
Sex” (contained in this document)
 Designing a “Determinants of Sexual
Phenotype” flowchart
Unit Two
 Reading assignments:
“Intersex Conditions: Causes,
Prevalence, and the Medical
Community’s Response” (contained in
this document); “What If It’s (Sort of) a
Boy and (Sort of) a Girl?,”
http://www.nytimes.com/2006/09/24
/magazine/24intersexkids.html?pagew
anted=all&_r=0/
 In-class completion of the “Predicting
Sexual Phenotype” activity
 Viewing of “Hermaphrodites Speak,”
http://www.youtube.com/watch?v=B
wSOngdR7kM/
Unit Three
 In-class completion of “Distinct or
Overlapping Populations?”
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STUDENT CASE STUDY—BAUER
Learning Objectives, cont’d.
4. To evaluate the experiences of
intersex individuals, in order to
identify the challenges they face
within the context of society’s twosex system
5. To describe how scientific texts
have contributed to the
perpetuation of the two-sex system
6. To formulate an argument that
either defends or argues against
application of the two-sex system
on college campuses
Related Activities/Assignments
Unit Four
 Reading assignments: “A New Era for Intersex
Rights,”
http://www.newyorker.com/online/blogs/news
desk/2013/12/a-new-era-for-intersexrights.html/; “In Amerika They Call Us Intersex,”
http://www.libidomag.com/nakedbrunch/archi
ve/hermaphrodites.html/; “A Girl Named
Steve,”
http://www.libidomag.com/nakedbrunch/archi
ve/girlsteve.html/; optional Pulitzer Prizewinning novel Middlesex, by Jeffrey Eugenides
 Unit Four discussion questions
Activities and readings included in Units One to
Three
Unit Five
 In-class completion of a debate: “The
Sex/Gender Continuum and The College Dorm”
Unit One: The Biology of Sex
Suggested Supplemental Readings
 Fausto-Sterling, A. 2012. Sex/Gender—Biology in a Social World [Chapter
Three]. New York: Routledge.
 Jones, R. E., and K. H. Lopez. 2006. Human Reproductive Biology, 3rd edition
[Chapter Five]. San Diego: Academic Press.
Sex is often discussed—particularly in traditional science textbooks—as being a
relatively straightforward issue, with clear categories of male and female. Yet a closer
examination of sexual phenotype (observable characteristics)—particularly in the case
of intersex individuals like Semenya—reveals that the physical expression of sex is
much more complex. In reality, sexual phenotype is comprised of six different
markers, and none of these is strictly binary. These markers include chromosomes,
gonads, hormones, internal genitalia, external genitalia, and secondary sex
characteristics. The role of each of these markers in contributing to sexual phenotype
is the focus of Unit One of this case study. Of note is the fact that prior to
masculinization or feminization of reproductive structures during human
development, all embryos—regardless of sexual genotype (genetic makeup of an
individual)—possess a neutral phenotype. In other words, the physical structures that
initially comprise the reproductive system are identical, and include gonads
(indifferent gonads or gonadal ridges) that are neither ovary- or testes-like, a set of
internal tubes (the Mullerian ducts and Wolffian ducts) that in no way represent (but
have the potential to form) masculine or feminine structures, and a collection of
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STUDENT CASE STUDY—BAUER
external tissues (including a phallus) that is undifferentiated (in other words, neither
penis- nor clitoris-like). These neutral tissues—and the structures that they have the
potential to form, depending on chromosomal and hormonal influences —are
depicted in Figures 1 and 2 and summarized in Table 1.
Figure 1. Development of Gonads and Internal Reproductive Structures
[OpenStax College - Anatomy & Physiology, Connexions Web site.
http://cnx.org/content/col11496/1.6/, Jun 19, 2013]
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STUDENT CASE STUDY—BAUER
Figure 2. Development of the External Genitalia*
[Human Physiology, Wikispaces.com, 2011.]
*Note that the perineum is the entire region that surrounds and includes all of the
structures pictured above.
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STUDENT CASE STUDY—BAUER
Table 1. Potential Contributions of Embryonic Reproductive Structures to Sexual
Phenotype
Embryonic
Structure
Potential Trigger
Key Factor(s) Influencing Differentiation
Genes
If SRY gene is present
and Rspo1 is
absent/inhibited then,
testes form
If Rspo1 is present and
SRY gene is absent,
then ovaries form
Mullerian
Ducts
Anti-Mullerian Factor
(AMF)
If AMF and receptors
are present, Mullerian
ducts degenerate.
If AMF or its receptors
are absent, Mullerian
ducts differentiate into
oviducts, uterus, cervix,
and the upper onethird of vagina
Wolffian
Ducts
Testosterone
If testosterone or its
receptors are absent,
Wolffian ducts
degenerate
genital
tubercle,1
urogenital
folds, and
labioscrotal
swellings
Dihydrotestosterone
(DHT, produced by action
of 5-reductase on
testosterone)
If testosterone and its
receptors are present,
Wolffian ducts develop
into epididymis, vas
deferens, and seminal
vesicles
If DHT and its receptors
are present the glans
(head) of penis
enlarges, the urogenital
folds fuse along
perineal raphe to form
shaft of penis, and the
labioscrotal swellings
form the scrotum
gonadal
ridges
In the absence of
androgens and,
possibly, the presence
of estrogen, growth of
the genital tubercle is
limited and becomes
the clitoris, urogenital
folds become labia
minora, and
labioscrotal swellings
become labia
Six Markers of Sexual Phenotype
Chromosomes
[For a review of chromosomes, DNA, and genes, visit this link:
http://www.genome.gov/26524120/.]
While much remains to be discovered regarding the genetic controls of sexual
differentiation, two genes in particular seem to play key roles in pushing the process in
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STUDENT CASE STUDY—BAUER
either a masculine or feminine direction. These two genes are the SRY gene (the “sex
determining region on the Y chromosome”) and the R-spondin gene (referred to as
Rspo1 and found on chromosome 1). Both play a role in directing the maturation of
the neutral gonads (the first step in sexual development). Rspo1 plays a key role in
directing the neutral gonads to form ovaries in embryos that have an XX (female)
genotype. When the SRY gene is present (in other words, in embryos that have an XY
or male genotype), SRY inhibits Rspo1, thereby causing the neutral gonads to form
testes.
Recent research indicates that humans can develop testes for gonads even with an XX
genotype (in other words, even with no Y chromosome or SRY gene) if they lack Rspo1
activity. In such cases, genetic testing reveals a feminine genotype (XX) in individuals
that have a masculinized phenotype.
Gonads and Hormones
Once the aforementioned genes (Rspo1, SRY) orchestrate gonadal differentiation, the
mature gonads (ovaries or testes) then produce hormones that direct the
differentiation of other reproductive structures (the internal and external genitalia). In
XX embryos, the neutral gonads differentiate into ovaries between weeks eight
through twelve. It is the estrogen (female sex hormone) produced by these ovaries—
as well as estrogen produced first by the mother that causes the internal and external
genitalia to feminize (as is described in the next section). In XY embryos (in other
words, when SRY is present and inhibits Rspo1 activity), the neutral gonads form
testes typically by week eight. These testes then produce two key hormones that play
a role in directing the internal and external genitalia to masculinize. These two key
hormones are testosterone (an androgen, or male sex hormone) and Anti-Mullerian
Factor (AMF; this hormone is also referred to as Mullerian Inhibiting Substance, or
MIS).
An important caveat to the success of hormonal activity is the availability of receptors
to mediate hormone actions. As Figure 3 illustrates, hormones exert effects on target
cells only when they can bind to their receptors (found either on the surface of cells or
inside cells). It is the hormone-receptor complex then that is able to alter the activities
of a cell/tissue /organ. If an individual lacks the appropriate receptor(s) for a given
hormone, that hormone—regardless of how much of it is present—will be unable to
exert changes within the body.
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STUDENT CASE STUDY—BAUER
Figure 3. Hormones Exert Effects on Cells/Tissues/Organs by Acting through their
Receptors
Internal Genitalia
Once the neutral gonads have developed into ovaries or testes, the hormones
produced by the gonads then act to establish internal reproductive sex. In other
words, they activate their receptors on the Wolffian ducts and/or Mullerian ducts to
cause the formation of masculine or feminine internal genitalia, respectively (listed in
Table 1 and illustrated in Figure 1).
If testes have formed from the neutral gonadal ridges, the AMF that they produce will
cause the Mullerian ducts to self-destruct, thereby eliminating the developmental
option of feminized internal reproductive structures. Testosterone— also produced by
the testes—will then act on the Wolffian ducts and cause them to form male internal
genitalia (vas deferens, seminal vesicles, and epididymis).
Conversely, if ovaries have formed from the neutral gonadal ridges, the Wolffian ducts
degenerate. This is thought to be due to the absence of appreciable levels of
testosterone or other androgens in embryos with feminized gonads. The Mullerian
ducts then partially fuse and differentiate into female internal genitalia (fallopian
tubes, uterus, cervix, and the upper one-third of the vagina). The process of Mullerian
duct differentiation is thought to be stimulated by estrogen (coming first from the
mother and then from the differentiated embryonic ovaries).
External Genitalia
At around the same time that gonadal hormones direct differentiation of internal
reproductive structures, they begin to do the same to external reproductive
structures. In their undifferentiated or neutral state, the external genitalia consist of a
phallus (the genital tubercle), genital folds, and genital swellings (see Figure 2 and
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STUDENT CASE STUDY—BAUER
Table 1). If the external genitalia are to masculinize (in other words, if they are to form
a penis or a scrotum), they must be acted upon by androgens (the male sex
hormones).
In order for androgens to masculinize the external genitalia, not only must androgen
receptors be present, but testosterone (the primary type of androgen made by the
testes) must be converted to a more physiologically active version of androgen called
dihydrotestosterone (DHT). DHT is produced from testosterone due to the actions of
the enzyme called 5--reductase, which is present in cells of the undifferentiated
external genitalia. When DHT is produced, it acts via androgen receptors (the same
ones that mediate testosterone actions) to cause the labioscrotal (genital) swellings to
fuse along the midline and form the scrotum, the urethral (genital) folds to fuse to
form the shaft of the penis, and the genital tubercle to form the tip of the penis
(depicted in Figure 2). The extent of virilization (including phallus length) can vary
quite significantly and is correlated with androgen concentration and sensitivity.
Two factors seem to account for the feminization of the external genitalia in embryos
that have ovaries for gonads. These factors include 1) the relative lack of gonadal
androgens (which eliminates virilization of the external genitalia as an option; while
the embryonic ovaries can produce some androgens, levels are minimal); and 2) the
presence of estrogens. Since the mechanisms accounting for feminization of the
external genitalia have not been studied as extensively as the process whereby the
genitalia are masculinized, our understanding of the role that estrogen plays in the
process of feminization is underdeveloped. Nonetheless, when these conditions are
present, the genital tubercle forms a clitoris, the genital folds become the labia minora
(the small labia of the vulva), and the genital swellings become the labia majora (the
large labia of the vulva; see Figure 2 and Table 1).
Secondary Sex Characteristics
Physical characteristics (other than reproductive structures) that we associate with
being masculine or feminine are referred to as secondary sex characteristics. These
characteristics appear most prominently at the time of puberty, when the gonads
begin to secrete significant quantities of the sex hormones (androgens and estrogens).
While both types of gonads (ovaries and testes) produce both types of sex hormones,
the testes produce significantly higher levels of androgens than estrogens, and the
ovaries produce greater levels of estrogens than androgens. It is the difference in the
ratio of sex hormones that accounts for the expression of masculine vs. feminine
secondary sex characteristics.
When estrogen concentrations predominate in the bloodstream, female secondary
sex characteristics are expressed. Some examples include breast development,
deposition of fat in a female-specific pattern (in the region of the hips and buttocks),
and widening of the pelvis. When androgen concentrations predominate in the
bloodstream, male secondary sex characteristics are expressed. Examples of these
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STUDENT CASE STUDY—BAUER
masculine characteristics include facial hair growth, heavier skull and bone structure,
and lengthening of the vocal folds of the larynx (which causes deepening of the voice).
As Unit 3 of this case study will highlight, the expression of secondary sex
characteristics is highly variable and correlates with levels of and sensitivity to sex
hormones.
Unit One Activity: Developing a “Determinants of Sexual Phenotype” Flowchart
In order to review, visualize, and summarize the process of sexual development,
design a flowchart that has incorporated into it the six markers of sexual phenotype
(chromosomes, gonads, hormones, internal genitalia, external genitalia, and
secondary sex characteristics).
Keep the following elements of design in mind as you construct your flowchart:


a processing step is denoted with a rectangular box; and
a decision is denoted with a diamond.
See Figure 4 for an example starting point for your “Determinants of Sexual
Phenotype” flowchart. Keep the flowchart handy for future reference, particularly
when engaging in Unit Two’s activity (“Predicting Sexual Phenotype”)
Figure 4. Suggested Beginning for a “Determinants of Sexual Phenotype” Flowchart
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STUDENT CASE STUDY—BAUER
Unit Two: Intersex Conditions: Causes, Prevalence, and the Medical Community’s
Response
Causes
As you learned in Unit One, a variety of different markers contribute to sexual
phenotype. While scientific texts typically portray sexual development as a binary
phenomenon (with all markers in a given individual being congruent—either feminine
or masculine), a survey of the natural world reveals much greater complexity in the
expression of sexual phenotype. Not only are the markers of sex not necessarily
congruent within a given individual (resulting in intersex phenotypes, the focus of this
unit), but there is also great variability in the expression of a particular marker (e.g.,
sex hormone levels) among individuals in whom all markers are congruent, and who
“fit” within the sex/gender binary (the focus of Unit Three of this case study).
So what does it mean to be intersex? A variety of definitions exist for the term
intersex, ranging from those that convey acceptance of natural variation in the
expression of sex (e.g., a sexual phenotype that doesn't fit the classic definitions of
male or female or a unique physical state) to those that are medicalized and suggest
the need or desire to “treat” or “fix” (e.g., “a disorder of sexual development” or DSD;
Feder and Karzakis 2008). In the past, intersex individuals were referred to as
hermaphrodites, and were divided into two categories: true hermaphrodites and
pseudohermaphrodites. True hermaphrodites are individuals whose intersex state is
due to genetic mosaicism (with some cells being XX and others XY).
Pseudohermaphrodites, on the other hand, are individuals who have a genotype that
is consistent from cell to cell (XX or XY, for example) but who have an individual gene
(or chromosome) difference that alters the pathway of sexual differentiation. As a
result, pseudohermaphrodites have both masculine and feminine characteristics.
[Note that while this case study uses the term intersex to refer to individuals whose
sexual phenotype doesn’t meet the classic definition of male or female, members of
the medical community, psychologists, and advocacy groups have recently agreed to
uniformly use the term DSD (“disorder of sexual development”) to refer to intersex
states (Romao et al. 2012). This controversial decision will be a topic of discussion later
in this case study.]
Intersex states don’t fit neatly within the sex/gender binary, typically (but not always)
due to the fact that some aspect of sexual phenotype isn’t congruent with sexual
genotype. Consider the case of Caster Semenya, whose story is highlighted in the
introduction to this case study. Semenya is intersex due to a condition known as
androgen insensitivity syndrome or AIS. Intersex individuals like Semenya have an XY
(masculine) genotype, and their sexual development proceeds through the initial steps
of masculinization that were described in Unit One of this case study: namely, the SRY
gene (present on the Y chromosome) suppresses Rspo1, which causes the neutral
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STUDENT CASE STUDY—BAUER
gonads to form testes. The testes then produce testosterone and AMF, as expected.
While AMF is able to cause degeneration of the Mullerian ducts, testosterone (and
DHT) are unable to fully act within the body due to the fact that individuals with AIS
are either completely insensitive to androgen actions (due to a total lack of functional
androgen receptors) or partially insensitive (due to a partial deficit in functional
receptors). Thus, androgens are unable to fully masculinize the Wolffian ducts and
external genitalia. As a result, individuals with AIS have the intersex phenotype
described in Table 2, and certain aspects of their sexual phenotype are incongruent
with sexual genotype.
Table 2. Phenotype of Intersex Individuals with Complete or Partial Androgen
Insensitivity Syndrome (AIS)
Marker of Sex
Chromosomes
Gonads
Hormones
Internal Genitalia
External Genitalia
Secondary Sex Characteristics
Differentiated Phenotype
XY (masculine)
testes (masculine)
testosterone, AMF, DHT (masculine)
Mullerian ducts degenerate; Wolffian
ducts either completely degenerate
(with complete AIS, or CAIS)
or partially develop
(with partial AIS, or PAIS)
vulva and vaginal opening (feminized)
with CAIS; ambiguous (partially
masculinized) with PAIS
feminized (with CAIS); partially
masculinized (with PAIS)
[For an animation of sexual development in embryos with CAIS and PAIS, see
http://www.aboutkidshealth.ca/En/HowTheBodyWorks/SexDevelopmentAnOverview
/AISand5ARD/TypicalDevelopmentBeforeBirth/Pages/CAISBeforeBirth.aspx/. ]
Incidence
CAIS and PAIS are just two of many intersex states that exist within the human
population (see Table 3 for other examples). Accurate statistics regarding the
frequency of occurrence of intersex states are difficult to obtain, for three distinct
reasons: 1) there is much secrecy and shame surrounding the topic, causing intersex
individuals and their families to hide their phenotype; 2) some examples of intersex
states are undetectable without in-depth medical examination (and thus go
undetected); and 3) there are no concrete guidelines for the definition of intersex.
Nonetheless, of those statistical analyses that have been conducted, estimates for the
incidence of intersex states range from 1 in 2,000 births to 1.7 per 100 births
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STUDENT CASE STUDY—BAUER
(Blackless et al. 2000). When reviewing Table 3, note the relative frequency of intersex
states vs. other unique phenotypes (e.g., red hair) within the human population.
Table 3. Estimated Frequency of Intersex* and Other Phenotypes in the Human
Population
Phenotype
Estimated Frequency/100 Live Births
Non-XX or non-XY
0.0639
(except Turner or Klinefelter)
Turner Syndrome
0.0369
Klinefelter Syndrome
0.0922
Complete Androgen
0.00760
Insensitivity Syndrome
Partial Androgen Insensitivity Syndrome
0.000760
Classic Congenital Adrenal Hyperplasia
0.00770
(CAH)
Late Onset CAH
1.5
Vaginal Agenesis
0.0169
True Hermaphrodites
0.0012
Idiopathic (unknown origin)
0.0009
Red hair**
1–2
Green eyes***
2
Albinism****
0.00005882
Males with height > 6’7”
0.05
Females with height > 6’1”
0.05
* Blackwell et al. 2000
**Garreau 2002
*** Sturm and Frudakis 2004
****Gronskov et al. 2007
Medical Community’s Response
Typically, one of the first questions asked of new parents is, “Is your baby a boy or a
girl?” This question can create a great deal of anxiety for parents of a newborn whose
reproductive phenotype does not fit within the two-sex system. They envision the
challenges that their child will face as they try to navigate a society that is entirely
structured around a binary view of sex and gender (e.g., public restrooms, gym
classes, college roommate assignments) and fear the social ostracism that will result if
their child doesn’t fit in. In order to prevent their child the anguish of marginalization
due to their intersex state, they—in consultation with their physician(s)—often take
significant medical steps to help their child assimilate.
When addressing intersex states in which the external genitalia are “ambiguous”
(neither masculine nor feminine), the traditional approach of the medical community
has been to strongly urge parents to choose a gender identity (male or female) for
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STUDENT CASE STUDY—BAUER
their child as soon as possible after birth. This is typically done in consultation with
medical professionals, taking factors such as chromosomal sex, genital appearance,
surgical options, potential for fertility, views of the family, and sometimes
circumstances relating to cultural practices into consideration (Lee et al. 2006; Romao
et al. 2012). After a sex is chosen, the medical team typically follows up with surgery
(usually several surgeries over the span of years) to align the genitalia with the chosen
sex. Given that surgically feminizing the genitalia is more easily accomplished than
masculinizing the genitalia, sex assignment of intersex newborns has traditionally
been skewed in the direction of feminization.
While the physicians and parents who employ this traditional, medicalized approach
to treating intersex conditions are well intentioned and certainly mean no harm, many
intersex individuals who have undergone “normalizing” surgery report that the
experience was damaging to both their emotional and sexual well being. From an
emotional standpoint, intersex individuals report feeling traumatized by repeatedly
having their genitals on “medical display,” as doctors, nurses, and medical students,
examine, touch, and photograph them. The serial surgeries and post-op treatments
involved with “normalizing” the genitalia can be painful and confusing for children.
Proper healing of a surgically created vagina, for example, requires daily dilation with
a hard instrument for months in order to prevent the vagina from closing up. Beyond
the potential for emotional trauma, “normalizing” surgeries also have the potential to
cause long-term damage to the sexual response. In particular, clitoral reduction
surgery (clitoroplasty, as is often performed to feminize external genitalia that has
been partially or fully masculinized during sexual development) can leave scar tissue
and/or nerve damage that permanently reduces sensation and thereby interferes with
the sexual response (Crouch et al. 2007; Piaggio 2014). While new surgical procedures
are being developed and implemented in the hopes of minimizing the loss of
sensation associated with clitoroplasty, the surgical community acknowledges that
“no surgery will be less damaging [to clitoral sensation] than the best possible
operation performed in a center of excellence” (Piaggio 2014).
Listening to the firsthand accounts of intersex individuals is particularly helpful for
understanding the negative effects (both physical and emotional) that can potentially
result from medical treatment of intersex conditions. Such firsthand accounts are
available in the film “Hermaphrodites Speak” (viewed within this unit of the case
study) and will also be reviewed and discussed later in Unit Four.
Unit Two Reading and Viewing Assignments

Weil, E. “What if It’s (Sort of) a Boy and (Sort of) a Girl?” New York Times,
September 24, 2006,
http://www.nytimes.com/2006/09/24/magazine/24intersexkids.html?pagewa
nted=all&_r=0/.
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STUDENT CASE STUDY—BAUER

Intersex Society of North America. 1996. “Hermaphrodites Speak,” YouTube
video, 34:59, http://www.youtube.com/watch?v=BwSOngdR7kM/.
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STUDENT CASE STUDY—BAUER
Unit Two Activity: Predicting Sexual Phenotype
Use the flowchart developed during the Unit One activity to guide your reasoning as you predict the sexual phenotype of the
following intersex states.
Intersex State
Complete
Androgen
Insensitivity
Syndrome
Partial Androgen
Insensitivity
Syndrome
Congenital
Adrenal
Hyperplasia
5-Reductase
Deficiency
(“Guevedoces”)
Description
no functional
androgen
receptors are
present
(androgen
insensitive)
reduced number
or sensitivity of
androgen
receptors
Chromosomes
Hormones
(androgens,
estrogens,
AMF?)
Gonads
(ovaries,
testes)
Internal genitalia
External genitalia
XY
XY
adrenal glands
produce high
XX
levels of
androgens
lacks enzyme that
converts
testosterone to
XY
DHT
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STUDENT CASE STUDY—BAUER
Unit Three: Secondary Sex Characteristics: Binary or Continuum?
The phenotypes and experiences of intersex individuals (in whom not all markers of
sex are congruent; addressed in Units Two and Four of this case study) call into
question the adequacy of the two-sex system for capturing the variability that exists
with respect to sex states in the natural world. The limitations of the system are also
called into question when examining variability in the expression of a particular
marker of sex (e.g., sex hormone levels) among individuals in whom all markers are
congruent, and who theoretically “fit” within the sex/gender binary. While the twosex system perpetuates the notion that sex differences in a given characteristic are
obviously binary (masculine vs. feminine), a closer examination of the data—like the
one you will conduct during Unit Three’s activity, “Distinct or Overlapping
Populations?”—indicates that this is not always the case.
Unit Three Activity: Distinct or Overlapping Populations?
Part One: Examine the data illustrated in Tables 4 through 6. Then, answer the
following questions:
1.
Select testosterone data from three of the methods of detection depicted in
Table 4. Then, for each of the methods of testosterone measurement,
construct a bar graph that illustrates the following: the mean levels + SD of
testosterone detected in males vs. females; the median levels + SD of
testosterone detected in males vs. females; and the range of testosterone
levels depicted in each sex.
2.
Are the data obtained from the various methods of detection equivalent, or is
there variability in levels of testosterone detected from method to method? If
variability exists, what might this mean for cross-study comparisons of
testosterone levels?
3.
Are the sex-specific ranges of testosterone levels distinct or overlapping within
each method?
4.
If you were provided with a serum sample for testosterone measurement in an
individual of unknown sex, would you be able to predict their sex based on the
level of testosterone you measured? Explain.
5.
Using data illustrated in Tables 5 and 6, determine the following: mean lengths
of the adult clitoris and penis; mean volumes of the adult clitoris and penis;
and the range of phallus lengths identified in each sex.
6.
Do the ranges for phallus length (of the clitoris, penis) overlap? If not, how
close do they come to overlapping?
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STUDENT CASE STUDY—BAUER
7.
Discuss your impressions regarding the range of penis and clitoris lengths
depicted in Tables 5 and 6. Are the lengths more or less variable than what you
would have predicted?
Part Two: Height is often cited as a sexually dimorphic characteristic, with males being
taller, on average, than females. In order to examine the variability that exists within
and between the sexes with respect to height, conduct the following experiment:
8.
While working in pairs, measure the height of each individual in the class. It is
important to precisely measure each individual’s height (rather than relying on
each individual to report their own height) since inaccuracies can result with
self-reporting. Each individual should anonymously write their measured
height on a piece of paper, along with the sex/gender they most closely
identify with in their day-to-day life. Collect the slips of paper, and identify two
students who will then enter the data into an excel spreadsheet.
9.
Post the data spreadsheet where it can be accessed by the entire class. Then,
work in pairs to calculate the following with respect to class measurements:
the mean height + SD of the class, of the females, and of the males; the median
height of the class, of the females, and of the males; and the ranges of heights
observed in the class, in females and in males. Conduct a t test to determine if
the difference in mean height observed between the sexes is statistically
significant. Graph your results.
10.
Discuss the results of your analyses. Were the ranges of heights observed in
the two sexes overlapping? Were the mean differences in heights observed
between the sexes statistically significant? If you were to know the height of an
individual, would you be able to predict their sex based on this informatio
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STUDENT CASE STUDY—BAUER
Table 4. Testosterone Values in Men and Women Obtained from 10 Different Methods of Measurement
Men (n = 50)
Samples, n
Median,
nmol/L
Mean,
nmol/L
SD, nmol/L
Range,
nmol/L
Women (n =
55)
Samples, n
Median,
nmol/L
Mean,
nmol/L
SD, nmol/L
Range,
nmol/L
ID/GCMS
Architect
i2000
ACS-180
Immuno Vidas
-1
Immulite
2000
Vitros
ECi
AutoDelfia
Elecsys
2010
RIA
Immunotech
Coat-ACount
DPC
50
19.5
45
20.3
50
23.0
50
20.6
50
15.9
50
16.3
50
16.0
50
22.3
50
15.9
50
16.5
50
20.5
21.2
19.5
23.7
21.7
16.5
18.8
17.8
21.9
16.4
17.0
20.7
10.8
8.2–
57.6
7.3
5.5–38.8
11.2
11.2
8.2
8.6–69.4 5.5–68.2 3.0–
38.5
9.7
6.2–53.4
10.0
9.0
4.5–56.7 7.6–54.4
8.8
9.3
3.4–49.6 2.9–45.8
9.3
6.2–52.7
55
2.1
54
3.1
55
4.0
55
2.5
51
1.7
53
5.0
55
2.0
55
4.9
53
1.2
54
2.5
51
2.6
2.2
3.5
4.3
2.8
2.2
5.5
2.2
5.1
1.6
2.7
2.8
1.2
0.6–
7.2
1.9
0.8–11.7
3.0
1.6
1.7–16.2 0.2–8.8
1.8
0.4–
10.9
3.3
0.9–18.4
1.4
0.2–8.5
2.6
0.1–13.8
1.3
0.2–7.6
1.4
0.4–9.0
1.6
0.7–9.4
Taieb, J., B. Mathian, F. Millot, M. C. Patricot, E. Mathieu, N. Queyrel, I. Lacroix, C. Somma-Delpero, and P. Boudou. 2003.
“Testosterone Measured by 10 Immunoassays and by Isotope-Dilution Gas Chromatography–Mass Spectrometry in Sera from 116
Men, Women, and Children.” Clinical Chemistry, 49(8): 1381–1395 (Adapted from Table 1, with permission from the American
Association for Clinical Chemistry).
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STUDENT CASE STUDY
Table 5. Measurements of Adult Female Genitalia (n=50)
Mean [SD]
Clitoral length (mm)
Clitoral glans width (mm)
Clitoris to urethra (mm)
Labia majora length (cm)
Labia minora length (mm)
Labia minora width (mm)
Perineum length (mm)
Vaginal length (cm)
Tanner stage (n)
19.1 + 8.7
5.5 + 1.7
28.5 + 7.1
9.3 + 1.3
60.6 + 17.2
21.8 + 9.4
31.3 + 8.5
9.6 + 1.5
4
46
9
41
14
34
2
IV
V
Same
Darker
Smooth
Moderate
Marked
Colour of genital area compared with surrounding skin (n)
Rugosity of labia (n)
Reprinted from Lloyd, J., N. S. Crouch, C. L. Minto, L- M. Liao, and S. M. Creighton.
2004. “Female Genital Appearance: ‘Normality’ Unfolds.” International Journal of
Obstetrics and Gynecology, 112: 643–646. Copyright © 2004, John Wiley and Sons.
Table 6. Measurements of Adult Male Genitalia
Penile shaft length (cm)
Penile shaft volume (cm3)
Glans penis length (cm)
Total penis length (cm)
Mean + SD
7.76 + 1.3
46.5 + 17.2
4.4 + 0.4
12.18 + 1.7
Range
5.5–12
20–97
3.5–5.5
9–17.5
Reprinted from Spyropoulos, E., Borousas, D., Mavrikos, S., Dellis, A., Bourounis, M.,
and S. Athanasiadis. 2002. “Size of External Genital Organs and Somatometric
Parameters among Physically Normal Men Younger than 40 Years of Age.” Urology,
60(3): 485–489. Copyright 2002, Elsevier.
Unit Four: The Experiences of Intersex Individuals in a Binary World
In Unit Four, you will read the firsthand accounts of individuals who are intersex and
navigating life within a binary world. These “anecdotal” accounts constitute a different
type of evidence than is typically sought in biological science contexts. From a social
science and policy perspective, however, these authentic voices provide a bridge for
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STUDENT CASE STUDY
society to understand the negative repercussions of standard medical approaches to
“treating” intersex states.
As you read these narratives, make note of the unique challenges intersex individuals
face within the context of society’s two-sex system. Then, during class, work within
small discussion groups to answer the questions posed below.
Reading Assignments
 Greenhouse, E. “A New Era for Intersex Rights,” New Yorker, December 2013,
http://www.newyorker.com/online/blogs/newsdesk/2013/12/a-new-era-forintersex-rights.html/.
 Long, L. S. “A Girl Named Steve,” Libido—The Journal of Sex and Sensibility,
Retrieved June 9, 2014,
http://www.libidomag.com/nakedbrunch/archive/girlsteve.html/.
 Moreno, A. “In Amerika They Call Us Intersex,” Libido—The Journal of Sex and
Sensibility, Retrieved June 9, 2014,
http://www.libidomag.com/nakedbrunch/archive/hermaphrodites.html/.
 Eugenides, J. 2002. Middlesex. New York: Picador Paperback.
Unit Four Discussion Questions
1. Pick two of the individuals highlighted in the readings and describe their
reproductive phenotype. What is the biological basis of their intersex state?
What aspects of their phenotype don’t allow them to “fit” within society’s twosex system?
2. Are there social challenges that these intersex individuals share in common?
What are the challenges most frequently cited in these narratives?
3. Based on the experiences of intersex individuals that were shared in the
readings, what recommendations would you make to the parents of intersex
children to eliminate (or lessen the severity of) these challenges? To
physicians?
4. Discuss the pros and cons of genital normalization surgeries/ procedures.
5. Can you envision a world in which intersex states are as readily accepted as
being male or female? Why or why not?
6. Discuss the implications of labeling intersex phenotypes as “disorders of sexual
development.”
Unit Five: A Debate—“The Sex/Gender Continuum and The College Dorm”
While many college campuses organize student housing along the binary of sex/
gender, some are beginning to address the inadequacy of sexed housing, since it fails
to be a comfortable or safe environment for students who don't fit within the binary
(e.g., intersex students). Yet offering gender neutral housing on college campuses has
not come without controversy, with some arguing that it will promote sexual
promiscuity and create a distracting environment, among other things (see
http://www.washingtonpost.com/local/george-mason-university-to-offer-gender22
STUDENT CASE STUDY
neutral-housing-in-fall-2014/2014/02/16/dd35a506-8e91-11e3-b22712a45d109e03_story.html.
In Unit Five, you will work to formulate a case that either argues for or against gender
neutral housing on college campuses. Prior to coming to class on the day on which the
debate will take place, the class will be divided into teams of five. Work with your
team to prepare written briefs on both sides of the issue, and come to class prepared
to argue either side. On the day of the debate, your team will be matched up against
another team in the class. Just before the debate, flip a coin to see which side your
team will represent, and select an individual from your team to start the debate
against another team. The debate itself will start with the pro side (in defense of
gender neutral housing) presenting for five minutes. Then a person representing the
con side (from the other team) will speak for five minutes. There is a five-minute
rebuttal by a second speaker on the pro side, followed by a five-minute rebuttal on
the con side. This is then followed by three-minute summaries by each side. Questions
from the audience will be permitted in order to evaluate the content and presentation
of the debate.
References
Blackwell, M., A. Charuvastra, A. Derryck, A. Fausto-Sterling, K. Lauzanne, and E. Lee.
2000. “How Sexually Dimorphic Are We? Review and Synthesis.” American Journal of
Human Biology, 12: 151–166.
Crouch, N. S., L- M. Liao, C. R. J. Woddhouse, G. S. Conway, and S. M. Creighton. 2007.
“Sexual Function and Genital Sensitivity Following Female Genitoplasty for Congenital
Adrenal Hyperplasia.” Journal of Urology, 179(2): 634–638.
Eugenides, J. 2002. Middlesex. New York: Picador Paperback.
Fausto-Sterling, A. 2000. Sexing the Body: Gender Politics and the Construction of
Sexuality. New York: Basic Books.
———. 2012. Sex/Gender—Biology in a Social World. New York: Routledge.
Feder, E. K., and K. Karzakis. 2008. “What’s in a Name? The Controversy Over
‘Disorders of Sexual Development.’” The Hastings Center Report, 38(5): 33–36.
Garreau, J. "Red Alert!," Washington Post, March 18, 2002,
http://www.garreau.com/main.cfm?action=chapters&id=20.
Greenhouse, E. “A New Era for Intersex Rights,” New Yorker, December 2013,
http://www.newyorker.com/online/blogs/newsdesk/2013/12/a-new-era-for-intersexrights.html.
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STUDENT CASE STUDY
Gronskov, K., J. Ek, and K. Brondum-Nielsen. “Oculocutaneous Albinism.” Orphanet
Journal of Rare Diseases, November 2, 2007,
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2211462/.
Intersex Society of North America. 1996. “Hermaphrodites Speak,” YouTube video,
34:59, http://www.youtube.com/watch?v=BwSOngdR7kM/.
Jones, R. E., and K. H. Lopez. 2006. Human Reproductive Biology, 3rd edition. San
Diego: Academic Press.
Karzakis, K., and R. Jordan-Young. 2014. “The Trouble With Too Much T.” New York
Times, April 11, 2014, http://www.nytimes.com/2014/04/11/opinion/the-troublewith-too-much-t.html?_r=0 .
Karzakis, K., R. Jordan-Young, G. Davis, and S. Camporesi. 2014. “Out of Bounds? A
Critique of the New Policies on Hyperandrogenism in Elite Female Athletes.” American
Journal of Bioethics, 12(7): 3–16.
Lloyd, J., N. S. Crouch, C. L. Minto, L- M Liao, and S. M. Creighton. 2005. “Female
Genital Appearance: ‘Normality’ Unfolds.” International Journal of Obstetrics and
Gynecology, 112: 643–646.
Long, L. S. “A Girl Named Steve.” Libido—The Journal of Sex and Sensibility, Retrieved
June 9, 2014, http://www.libidomag.com/nakedbrunch/archive/girlsteve.html.
Moreno, A. “In Amerika They Call Us Intersex.” Libido—The Journal of Sex and
Sensibility, Retrieved June 9, 2014,
http://www.libidomag.com/nakedbrunch/archive/hermaphrodites.html.
Check Link!
OpenStax College Anatomy and Physiology, Connexions Web site. 2013. 2915—
Sexual Differentiation, http://cnx.org/content/col11496/1.6/.
PIaggio, L.A. 2014. “Congenital Adrenal Hyperplasia: Review from a Surgeon’s
Perspective in the Beginning of the Twenty-first Century.” Frontiers in Pediatrics,
1(50): 1–7.
Romao, R. L., J. L. Salle, and D. K. Wherrett. 2012. “Update on the Management of
Disorders of Sexual Development.” Pediatr Clin North Am, 59(4): 853–869.
Spyropoulos, E., D. Borousas, S. Mavrikos, A. Dellis, M. Bourounis, and S. Athanasiadis.
2002. “Size of External Genital Organs and Somatometric Parameters among Physically
Normal Men Younger than 40 Years of Age.” Urology, 60(3): 485–489.
Sturm, R. A., and T. N. Frudakis. 2004. “Eye Colour: Portals into Pigmentation Genes
and Ancestry.” Trends in Genetics, 20: 327–332.
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STUDENT CASE STUDY
Svitek, P. “George Mason University to Offer Gender-Neutral Housing in Fall 2014.”
Washington Post, February 16, 2014, http://www.washingtonpost.com/local/georgemason-university-to-offer-gender-neutral-housing-in-fall2014/2014/02/16/dd35a506-8e91-11e3-b227-12a45d109e03_story.html.
Taieb, J., B. Mathian, F. Millot, M. C. Patricot, E. Mathieu, N. Queyrel, I. Lacroix, C.
Somma-Delpero, and P. Boudou. 2003. “Testosterone Measured by 10 Immunoassays
and by Isotope-Dilution Gas Chromatography–Mass Spectrometry in Sera from 116
Men, Women, and Children.” Clinical Chemistry, 49(8): 1381–1395.
Weil, E. “What if It’s (Sort of) a Boy and (Sort of) a Girl?” New York Times, September
24, 2006,
http://www.nytimes.com/2006/09/24/magazine/24intersexkids.html?pagewanted=all
&_r=0/
Wikispaces.com. 2011. Human Physiology,
http://humanphysiology2011.wikispaces.com/.
About the Author
Angela Bauer recently assumed the position of professor and chair of biology at High
Point University, after spending sixteen years within the University of Wisconsin (UW)
System, where she served as chair of human biology and special assistant to the
provost (Institutional Assessment) at UW–Green Bay. In addition to conducting
scientific research on the negative health effects of exposure to environmental
endocrine disruptors, she also conducts research in the field of the Scholarship of
Teaching and Learning (SoTL). Her specific SoTL interests include the impact of active
learning strategies on academic performance and engagement within the science
classroom (in both general education courses for non-majors and upper-level courses
for majors), the benefits of the flipped classroom for providing opportunities that
foster deep disciplinary learning within the sciences, and inclusive classroom practices
that close the opportunity gap between majority and underrepresented students in
the sciences. For her work on successfully closing the opportunity gap in an
introductory biology course at UW–Green Bay, she was awarded the UW System
Board of Regents Diversity Award (Individual Category) in February 2013. Both at UW–
Green Bay and now at High Point University, she has served as co-director of a
Teaching Scholars Program, which engages faculty in yearlong SoTL projects designed
to foster teaching innovation and gather evidence regarding the impact of specific
classroom strategies on student performance.
25