Ch. 2 – Biology, Sex, and
Gender: The Interaction of
Nature and Environment
Robert Wonser
Biology or the Environment?
• How much of who you are is in your DNA?
• How much of who you are is a result of your
upbringing/socialization?
• We have long categorized and documented differences between
men and women, why is this problematic?
• We go beyond simply categorizing difference; particular attitudes,
aptitudes, and behaviors are imbued with differential value one
behavior is then considered superior to the other—the “other” almost
always being associated with female.
• “There is nothing essential—that is, universal and unvarying—in the
natures of women and men” – Tarvis
• The social influence may the biological as much as the biological
influences the social.
Sex Chromosomes and Sexual
Differentiation
• We’re usually born with 46 chromosomes in 23 pairs.
• One pair of chromosomes is referred to as the Sex
chromosomes because it plays the primary role of
determining whether a fertilized egg will develop into a
male or female fetus.
– X and Y  male, X and X  female
– Mother always contributes an X (she’s always got an XX pair)
the fetus’s sex is determined by the father (an X female, a Y 
male)
• The 6th week the child’s sex is established; prior to this
all embryos are sexually bipotential  they are
anatomically identical, each possessing the necessary
parts to develop into a male or female.
Chromosomal Abnormalities and
Gender
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Before an egg is even fertilized, chromosomal errors can occur during
sperm production that later result in the birth of individuals with an abnormal
complement of sex chromosomes.
During sperm production, the chromosomes divide and duplicate
themselves in a two-stage process called meiosis.  usually produces
either X chromosome carrying sperm or Y chromosome carrying sperm.
Sometime the sperm fail to provide properly, a problem called
nondisjunction if this occurs during stage one meiosis, two kinds of sperm
are produced: those with both an X and a Y and those with neither an X nor
a Y.
If one of these sperm fertilizes a normal egg, the offspring will either be XXY
or XO.
If nondisjunction occurs during the second meiotic division (stage two),
three kinds of sperm are produced: XX, YY, and those with no sex
chromosomes.
Eggs fertilized by these sperm would produce offspring that are XXX, XYY,
and XO respectively.
Turner Syndrome
• Do these chromosomal abnormalities have any effect on gendered
behavior or personality traits?
• Individuals who are XO have Turner Syndrome. Since they don’t
have a Y chromosome they do not develop as males, however, since
they have no second X chromosome either they have no gonadal
tissue and produce no sex hormones.
• Since they have external genitalia that appears to be female they are
raised as female.
• Despite the absence of sex hormones, research reveals stereotypical
femininity in their beliefs and behaviors and personalities.
– Compared to normal girls: less likely to be or be labeled ‘tomboys’, like to
wear ‘frilly dresses’ more, strongly preferred girls to boys as playmates,
played only with girls toys, and expressed an intense interest in caring for
babies.
• Since there is no biological explanation how do we account for this
behavior?
• Intensified feminization by parents to make up for lack of hormones.
Klinefelter Syndrome
• Women and men with an extra X chromosome (XXX and XXY,
respectively) differ considerably
• XXX women show few visible signs of abnormality but tend to be
taller and have higher incidence of learning disabilities.
• XXY chromosome combination is known as Klinefelter syndrome
which produces a number of physical problems.
• Physically look more male than female, although they usually have
small penises and testes.
• At puberty grow taller than average, hips usually feminize, may
have some breast development, testes do not enlarge, do not
produce sperm, voice do not deepen, and they develop little or no
pubic and facial hair.
• Men tend to be timid and socially isolated, uninterested in women,
dating, or sex.
• These difficulties could be a result of the condition or indirectly
related.  coping could lead to emotional trouble.
The Case of XYY syndrome
• There is an unusually high incidence of the abnormality among
institutionalized and incarcerated men: 10-20 ties greater than the
general population!
• How do we explain this? Biology?
• Why would an extra Y chromosome predispose men to behave
violently?
• Y testosterone  aggression  violence
• XYY offenders were mostly property crimes
• The overrepresentation of men among the institutionalized and
incarcerated can be explained by social and psychological factors.
• There is an emphasis on the interaction between biology and the
environment: the extra Y chromosome (biology) produces unusual
height and low intellectual functioning in the men who have it, which
may lead to negative social reactions to their appearance and
behavior (environment)  higher probability that XYY men, if
identified, will be institutionalized or incarcerated.
Prenatal Hormones and Gender
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Adrenogenital syndrome (AGS) is also called congenital adrenal
hyperplasia (CAH) occurs in 1/5,000 to 1/15,000 births and is caused by a
malfunction in the mother’s or the fetus’s adrenal glands or from exposure of
the mother to a substance that acts on the fetus like an androgen.
Can affect males and females both genetic females (individuals whose genetic
sex is female and who were exposed to androgens in the womb after their
internal reproductive organs had developed) are more severely affected.
 the androgens have a masculinizing effect on the genitalia (enlarging of the
clitoris, resembling a small penis, or the labia may be fused and the vagina
may be closed)  often fixed through surgery since the internal genitalia is
functioning)
Researchers have studied these girls and when compared to normal girls
have found striking differences:
AGS girls tend to describe themselves (as do their parents) as tomboys,
prefer slacks and shorts over dresses and skirts, choose ‘boy toys’, prefer
boys as playmates and prefer rough and tumble play.
However they aren’t significantly more aggressive than normal girls and desire
romance, marriage, and motherhood in their futures.
Androgen Insensitive Syndrome
• Sometimes an XY fetus has a genetic defect that
causes it to be unresponsive to the androgens
its testes secrete, a condition known as
Androgen-insensitive syndrome.
• Sometimes called ‘XY females’ because even
though they possess the sex chromosomes of
normal males (XY), they are born with the
external genitalia of females.
• Are they predisposed to act masculine?
• Research shows they as feminine as XX
females.
DHT deficiency syndrome
• A condition that involves partial rather than total
androgen insensitivity is DHT deficiency syndrome,
also called 5-alpha-reductase deficiency.
• DHT is the hormone that is responsible for the
development of the external genitalia.
• Born with normal, undescended testes and internal male
accessory organs.
• Externally they have female genitals that are partially
masculinized (enlarged clitoris that looks like a small
penis and sometimes an incomplete scrotum that looks
similar to the labia).
•  presence of testes, at puberty, testosterone changes
the genitals: the penis grows, the scrotum descends, and
the body becomes more muscular.
Genital Ambiguity: What can it
teach us about gender?
• How do we usually respond to it? Surgery to “correct” genital
ambiguity. Why do we do this?
• Research suggests that the development of masculine or feminine
gender identity is quite independent of either the presence of a pair of
XX or XY sex chromosomes, or the production of particular hormones.
• Neither sex, nor gender is dichotomous
• Sex could refer to chromosomal sex, hormonal sex, gonadal sex, or
genital sex: usually these are the same).
• Similarly, gender (masculinity or femininity) is far from being an
either/or phenomenon, includes a broad spectrum of attitudes,
behaviors and social expectations that we acquire through our
lifetimes, through interactions with one another and experience in
various environments.
• Other societies: sex and gender fluidity is the norm and is accepted as
natural.
• However, it is not a question of “if” biology influences human behavior
but rather of “how” and “how much”
The Case for His and Hers Brains
• Research is focused on how our brains are organized.
• Differential organization of the brain may be responsible
for behavioral differences and sexual orientation.
• Difficulties:
– Most studies focus on animal brains (particularly rats). Studies
trying to see if sex differences in rats brains are there in human
brains are unsuccessful.
– The human brain changes as people age and in response to
experience and environmental conditions.
– We do not yet fully understand how the way specific parts of the
brain are structured affect how they function.
Brain Structure
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Each hemisphere seems to “specialize” in certain functions or tasks
This specialization is referred to as hemispheric asymmetry or brain
lateralization
Left hemisphere (which controls the right side of the body) is responsible for
language
Right hemisphere (which controls the left half of the body) is thought to
handle emotions.
Men are more lateralized than women—that is, they are more dependent on
one hemisphere of their brains to complete certain tasks whereas women
draw on both hemispheres.
Te corpus callosum—the mass of tissue and nerve fibers that connect the
two hemispheres of the brain—is 23% larger in females. This may allow for
more communication between the two hemispheres.
Are these sex differences in the brain present at birth or do they develop
through the differing socialization process of men and women?
“Everything is biologically determined at one level, but its expression is
always an interaction with an environment.” (Wallen)
Sexual Orientation and the Brain
• LeVay’s study or post mortem brains showed that the one
node of the anterior hypothalamus (an area of the brain
that scientists speculate may play a part in sexual
behavior) was three times larger in the heterosexual men
than in the homosexual men, whose nodes were closer to
the size of heterosexual women’s brains.
• There is also research showing a genetic link to sexual
orientation
• Methodological problems with the research:
– What about lesbians? Rarely studied but when they are their
results are little different than heterosexual women.
– Sample size is very small. LeVay studied only 41 brains.
– No one can say for sure whether or not the structural differences in
the brain caused sexual orientation or were created early in life
along with sexual orientation.
“My hormones made me do it”
• What about the boy who had his penis
almost completely destroyed at eight
months old?
• How successful were the socialization
attempts to raise him as a her?
• Why did it turn out this way?
• Was it because the brain had already been
exposed to testosterone irrevocably
masculinizing her?
Testosterone and Gender
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Both males and females produce the same sex hormones but in different
amounts. Males  more testosterone and androgens and females 
estrogen and progesterone.
Countless studies show that lab animals injected with testosterone engage in
‘male’ behavior (rough and tumble play, impatience and fighting) regardless of
sex.
Cautious: there is tremendous variation in animals
– Ex: Female gerbils and hamsters are just as aggressive as males without
being injected
In humans, findings do indicate that high levels of circulating testosterone are
correlated with edginess, competitiveness and anger.
Specific relationship between testosterone and behavior is elusive because:
Hormones fluctuate throughout the day and in response to environmental
stimuli
So, testosterone is correlated with competitiveness, more testosterone=more
competitive? Not so fast…
Recent research shows that testosterone levels rise and fall in response to
competitive challenges.
One study testosterone rises before a tennis match (or chess game), down
as the match is being played, and up again if victorious, down is the player
lost.
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 maybe it is not the relationship between testosterone and aggression that
is significant, but rather the relationship between dominance/eminence and
testosterone.
Dominance refers to an elevated social rank that is achieved by overcoming
others in a competitive confrontation
Eminence is where elevated social rank is earned through socially valued
and approved accomplishment
Finally, testosterone is only one of several chemicals interacting in the body
that affect human behavioral response. Ex: neurotransmitters such as
norepinephrine
Human social behavior is highly governed by the situation or context in
which it occurs and this may override the potential effects of hormones or
chemicals.
Studies show women can be just as aggressive as men if the situation calls
for it or thy are rewarded for doing so.
Such research would indicate that women inhibit aggression due to social
norms of gender behavior for women.
Cross-cultural research also shows that women may behave as
aggressively as men, but how they express aggression (e.g. verbal versus
physical) may be structured by their culture’s gender norms.
For both males and females, aggressiveness decreases as age and
education increase
Women, Hormones, and Behavior
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The notion that women’s personality and behavior is dictated by their hormones is an
old one.
The word androgen comes from the Greek word for “man” while estrogen comes from
the Greek word for “frenzy”
Premenstrual syndrome was not discussed in the medical literature until 65 years
ago.
Is PMS a verifiable syndrome?
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Studies are plagued by methodological problems:
Rely on self reports; notoriously unreliable.
Societal negative attitudes towards menstruation affect how women experience it (and if they
experience it)
If it is a medical entity, there is no consensus about what causes it.
Could be a drop in progesterone days before the cycle empirical evidence is
limited.
One reason researchers may only find negative reactions toward menstruation is that
the questionnaires only ask about negative effects.
When this is accounted for, the effects can be classified as slightly positive.
Bottom line: uncertainty exists about what and if PMS is and any sort of medical
treatment should be suspect.
Postpartum Depression Syndrome
• 50-80% of women report feelings of sadness, tension and irritability
during the first two weeks after the birth of their baby. This usually
disappears quickly though
• 10-20% of women experience post partum depression.
• Hormonal changes and the sudden drop in progesterone are the
most widely accepted cause.
• However, incidence and severity of post partum emotional disorders
are directly related to the amount of social support available to new
mothers, as well as the amount and type of socioenvironmental
stressors (e.g. financial or housing difficulties, marital problems, the
number and age of other children in the household) to which they
are exposed.
• Most likely to experience post partum emotional disorders? 
• Moen who are isolated in their homes, who lack family and social
support networks, and who are exposed to serious and prolonged
stress.
The Interaction of Biology and
Culture
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We tend to assume that biology comes first and the social acts upon what biology
has constrained for us and that we progress upon a linear path and that the
individual has no role or active part in his or her own development.
In contrast, continuous and transformative change occurs throughout a person’s
lifetime and that person’s behavior can alter not only his or her environment, but
also his or her biology and physiology.
Social constructionist critiques have been ventral in challenging the oppressive
aspects of many biological determinist theories, but they have tended to reinforce
the dichotomous view of biology versus environment rather than transcending it.
To focus on one or the other is to only tell half the story.
Our bodies are social as well
A transformative account of gender development—one that examines how
culture and individual behavior may impact biology and physiology as well as vice
verse—underlies the pitfalls of using biological principles to justify gender
inequality and also overcomes a longstanding preoccupation with sex differences.
The existence of difference, even if biologically caused, does not imply a
hierarchical ordering, nor does it imply that one behavior or trait is inherently
superior to another.
Women and men are different in observable ways is a fact; however, that either is
discriminated against on the basis of these differences is a social injustice.