Lecture 9 Flashcards
Sex versus gender
SEX refers to the biological sex
GENDER refers to the psychological sex
Factors influencing gender identity:
1) biological factors (genes, hormone exposure)
2) environmental factors (society, cultural and parental)
3) the interaction between the two
Can Gender Be Assigned?
David Reimer had a botched circumcision but was one of two male twins
It was decided to remove his testicles and give E then raise him as female
Despite this Brenda never fit in, felt male
He was XY and so was exposed to androgens in development
When he found out what had happened he transitioned and considered himself male
Eventually, he killed himself. This should not have happened
Gender Dysphoria
XX or XY chromosomes
-Gender is opposite biological sex
DSM 5 Diagnostic criteria
- A marked incongruence between one’s experienced/expressed gender and primary and/or secondary sex characteristics
- A strong desire to be rid of one’s primary and/or secondary sex characteristics
- A strong desire for the primary and/or secondary sex characteristics of the other gender
- A strong desire to be of the other gender
- A strong desire to be treated as the other gender
- A strong conviction that one has the typical feelings and reactions of the other gender
Change from DSM-IV
NO LONGER CALLED A DISORDER
Symptoms of gender dysmorphia
- Belief that they will grow up to be the opposite sex
- Expressed desire to be the opposite sex
- Disgust with their own genitalia
- Withdrawal, isolation, depression
- Not due to a physically intersex condition
Old vs new treatment of gender dysmorphia
Traditionally:
Thought to be entirely a disorder of the mind
Attempted to treat this through psychotherapy
Now recognized that there may be biological basis: psychological intervention is ineffective
Combination of causes for gender dysmorphia
Prenatal hormonal imbalances
Genetic abnormalities
Defects in normal human bonding - much greater chance of having experienced child abuse
No strong bond with parent
Society doesn’t like continuum….
-Societal constraints: only universally accepting of male and female as gender identities.
-Confronted by discrimination or harassment regularly
-Don’t mess with status quo
-Transgender individuals now protected under the Human Rights Act under the grounds of sex – as of 2017
-Quebec and other provinces following suit
(actually QC did it before, 2016)
2D:4D story – physical measure for in utero androgens
- Men typically have longer ring than index fingers
- Females have similar index and ring fingers, or longer index finger
- Ratio of 2D:4D measure of in utero androgen exposure, androgen exposure is negatively correlated with ratio (males have a smaller ratio)
-Serves as a pretty reliable measure of early androgen exposure
When we want to research sex-related variations in the brain:
We are interested in effect of testosterone in determining sex differences
Cognition, behaviour, orientation, identity
Biological mechanism for maleness
Contrast to traditional perspective: gender is based on nurture how a child is raised
Difficult – accurate studies in humans so many in animals
Examine people with CAH, CAI, or mothers treated with androgens
We wind up using either animals or rare human conditions as we cannot expose humans to androgens
Melissa Hines did this
Hormones and play study
Male–typical play
- Rough and tumble
- Outdoors
- Cars
Female–typical play
- House, crafts
- Indoors
- Dolls
Subjects had
Congenital adrenal hyperplasia, maternal androgen admin and naturally higher maternal androgens
Naturally higher maternal androgens
Sometimes assessed in mothers during pregnancy if there is reason to do so, if not also use digit ratio
Androgen exposure was correlated by Hines with male typical behaviour in females
Hormones and play study resultd
Female typical play
- Typical girls do lots of female typical play
- CAH girls did much less of it but still more than CAH boys and typical boys
Male typical play
- Girls with CAH do more than typical girls
- Less than boys with CAH and typical boys
Using the Preschool Activity Inventory which measures sex-typed childhood activities (is a more general measure and takes into account HOW the children’s played e.g. using a doll in a male way)
You see a magnification of the results. CAH females no different from CAH boys and normal boys on the PSAI and far higher than normal girls.
Play in primates
No socializing role Give an array of toys Females choose female typical toys Males choose male ones Teases apart nurture and nature Probably there is a biological drive for this
Sex differences in other activities
Targeting, fine motor, spatial ability and aggression
Higher in males
Verbal fluency and empathy
Higher in Females
Male preference for vehicles and rough and tumble
Males prefer Prefer spatial movement?
Sex difference in primary visual cortex
Toy preference reflects underlying basic characteristic of stimuli
Sex differences in brain development
Testosterone exposure masculinizes the brain
Rodents and monkeys: castration and hormone administration
Males have larger brains, females deeper gyri/larger sulci
Women thicker cortex
Testosterone enlarges sexually dimorphic brain regions
Medial hypothalamus, bed nucleus of stria terminalis (BNST), and amygdala
Some changes linked to gendered behaviour
Amygdala in rough and tumble play
Hormones and Gender Identity
Pubertal hormones activate what was organized early in life
Act in brain areas organized in development
Females with CAH have identify as male more often
CAIS almost always identify as female even though XY
Klinefelter’s reports higher incidence of gender ambiguity and transgenderism
Could be that changes in androgens contributes to changes in gender
Neurobiological differences in gender dysphoria Hypotheses
Major testosterone induced sex difference in rats brains
SDN of MPOA
Decided to examine humans on: post-mortem examination of the interstial nucleus of the anterior hypothalamus (INAH) does it differ in:
sexes
Male to female trans
Trans individuals?
Effect of adult changes in gonadal hormones?
Size based on number of neurons AND number of synapses is different with increased androgens
Neurobiological differences in gender dysphoria (results)
Female gender consistently lower volume and neurons than male in INAH
- Male to female trans – smaller than men regardless of hormone replacement treatment
- Female to male trans in range of biological men
Adult hormone makes no difference
Some evidence this region is larger in hetero than homosexual men
Inconsistent results
Castrated males (had prostate cancer so removed) later in life had no androgens but still no difference in INAH which points to an early organizational effect
Post menopaused women’s INAH does not change size either
Getting up to date on transgender differences pre gender affirming hormones
Are MtF individuals more like CF (and differ from CM), and vice versa
-Prior to hormone therapy use
Cognitive tasks:
-MtF perform better on verbal tasks than CM, FtM perform worse than CF
-Conceptual style more similar to indentified gender too MtF perform similarly to CM on spatial tasks
-Brain structure:
Cortical thickness, total grey matter, corpus callosum shape and resting state functional activity all more similar to identified gender
Some discrepancy here
So overall there are consistent differences
Some difference between MtF and CM, and FtM and CF
Not always - sit in between the two biological sexes on some measures?
Could they be somewhere in the middle on a spectrum?
Struggle with sex as continuum in our society
Societies with less discrete sex categories less difficulty with trans individuals
When research gets it wrong….
BAD research on sex and gender
Research from a looong time ago
-Is there a link between androgens and masculine behaviour in CAH?
YES – but unclear back then
-Evidence that tomboy behaviour in CAH females linked to androgens
Froukje and Slijper think not…..
-Develop their own test of “girlishness” and compare CAH to childhood diabetes
Also looked at parental confidence of gender
Sophia task assesses girl and boy –ishness
-See consistently lower scores in boys and higher in females
Then compare this to health statuuses including CAH, diabetes, generically sick and bother/sister having CAH
See highest scores in healthy girls
-All sick children scored closer to neutral
-Did note that CAH females particularly low
(On sophia task)
They examined the effect t in females with salt-wasting CAH
Saw that CAH with salt-wasting had highest masculinity
Effect driven by this subset of CAH
Salt wasting because less aldosterone
-More severe illness than CAH without this
The concluded that THE SEVERITY of illness causes more masculinize behaviour
Also saw relation between parental sex confusion at birth and masculinization on Sophia
Parental uncertainty about gender masculinizes behaviour (could be intersex)
Issue with Conclusions of the Sophia study
Salt wasting suggests more complete lack of 17B-hydroxylase
Suggests higher levels of androgen production
This is a confound – can explain BOTH of conclusions
More androgens would mean more masculinized behaviour
Also masculinize genitalia more, causing parental concern
Sophia task not validated against other measures
Boys and girls differed, but does it measuring same thing as other tests?
Rely heavily on a few responses that are not validated
Confirmation bias in action!!
Skepticism is key
Hormones and Sexual Orientation
Pubertal hormones activate what was organized early in life. This can cause an issue if everyone around you is interested in the opposite sex and you are not.
Even if adjust hormone in childhood and adulthood see differences
Females with CAH identify as male more often
Higher incidence of homosexuality as well
CAIS almost always identify as female with sexual interest in males. Sexual orientation here is inline with gender, not sex.
Hormones and Sexual Orientation
Kinsey
Evidence for sexuality existing along a continuum too
Kinsey was a biologist studying Gall Wasps, made to teach human sexuality
No scientific information so decided to work it out
Devoted remainder of career top studying sexual behaviour
-Sexuality does not seem binary – huge variation
-Homosexuality not as aberrant as expected
He may have based this off an extreme sample but the point stands
The Kinsey rereport and the Kinsey Institute
Hormones and Sexual Orientation
Some 2D:4D studies suggest that larger ratio linked to male homosexuality (2D same as or larger than 4D)
- Less testosterone = larger ratio = increased homosexuality
- Results ambiguous
Birth order linked to sexual orientation
- Mother antibodies against T, activated more rapidly in later pregnancies
- Males later in birth order = increased homosexuality
2D:4D and homosexuality
- Homosexual males larger ratio than heterosexual
- Homosexual females smaller ratio than heterosexual
In neither case were the 2D:4D ratios as extreme as they were in hetro men and women. Hence, it seems possible that homosexuals sit somewhere in the middle of a spectrum of gender
Getting up to date on biological basis of homosexuality
Quick look at updates in brain changes associated with homosexuality
Red = interstitial nucleus, similar in hetero men and homo women
-It is larger in hetro men and homo women
Brown = hemisphere size, asymmetrical in hetero men and homo women
-More equal in homosexual men and hetrosexual women
Green = olfactory regions, pheromones activate differently
- Larger in hetrosexual women and gay men
- Could mean that smell and pheromones’ affect them differently
Blue = right amygdala more connected in hetero men and homo women, leftt amygdala more connected in hetero women and homo men
- Likely a target for sex dependent behavior.
- Larger in childhood = more rough play in childhood
- Larger in adult = Changes in sexual behavior
Yellow = anterior commissure, women and homo men larger than hetero men
Development of physical sex, psychological sex and sexual orientation across development
- Organization can alter physiology and psychology
- Mediated by hormones
- There are many ways this can be altered
- These may contribute to gender and sexuality
- It is possible hormone levels change and alter psychological stuff even AFTER they already caused physiological changes
- This could result in a masculinized brain that does not match one’s biological sex
Sex-related variation in human behavior and the brain (basics)
● Prenatal testosterone levels differ between sexes as early as week 8 of gestation
● Differences in hormone levels seem to affect sex-typical childhood behaviors (which
were recently believed to result only from sociocultural influences)
● Brain structures responsible for these hormone-induced behavioral outcomes include the
hippocampus and amygdala, in addition to interhemispheric connectivity and cortical
areas involved in visual processing
Human sexual differentiation
● Growing evidence that prenatal androgen exposure influences other things (aside from
sex-typical play) such as sexual orientation, gender identity, personality characteristics,
and moroe performance
Toy Story
● Traditional developmental psychological theories suggested that children acquire sex-typical behavior through social leanring and cognitive developmental processes that lead to gender identification and valueing od behaviors associated with one’s gender
○ We now have evidence suggesting that prenatal testosterone also plays a role
Hormones and Sexual Differentiation
● Girls exposed to unusually high levels of androgens prenatally (typically due to CAH) show increased male-typical play and decreased female-typical play
● Children whose mothers took androgenic progestins during pregnancy show increased male-typical play whereas children whose mothers took anti-androgenic progestins show
decreased male-typical play
Addressing the Counterarguments about hormonally changed behavior
● Was once suggested that the abnormal external genitalia of CAH girls masculinizes their
behavior rather than the action of androgens in the brain
○ However more recent studies have shown that this is not the case
● It’s unlikely that socialization accounts for the relation between prenatal hormones and
postnatal behavior
● Studies of non-human primates have found sex-typed toy preferences similar to those
gound in humans
A new perspective on toys
● Sex-typed color preferences do not seem to underlie sex-typed toy preferences
● Suggested that boys like toys that can be moved in space and increased androgen
exposure may play a role in this by altering the visual system
Early hormonal influences on sexual orientation and gender identity
● CAH women show reduced heterosexual orientation
● Normal variability in prenatal testosterone levels has not been related to sexual
orientation
● 2D:4D ratio: the ratio of the second finger of the hand to the length of the fourth finger
○ Higher in females than males
○ Thought to reflect the amounts of prenatal androgen exposure
● Study with 200,000 individuals who measured their 2D:4D and reported their sexual
orientation online showed that 2D:4D related as predicted to sexual orientation in males,
but not females
○ Another study found the opposite
○ Finger ratios are probably a weak correlate of androgen exposure
Early hormone influences on personality, cognition, and motor performance
(in sexes)
● Empathy is higher in females
● Physical aggression is higher in males
● Females with CAH show reduced empathy
● Testosterone measured in amniotic fluid relates negatively to empathy in both sexes
● One study showed that CAH females are more accurate at throwing balls and darts at
targets
○ Result was not accounted for by increased muscle strength
● Results concerning differences in cognitive abilities are mixed
Sex-related psychiatric disorders
● Testosterone has been suggested to contribute to ASD, OCD, and Tourette’s syndrome
Sex differences in the brain
● Total brain volume (as with body size) is larger in males than females
● Males have larger amygdala, females have larger hippocampus
● Females have greater cortical thickness in many regions
● Females have increased gyrification in frontal and parietal cortex, and perhaps more
efficient use of white matter
○ Perhaps to compensate for lack of volume
● Third interstitial nucleus of the anterior hypothalamus (INAH-3) is larger in males than
females
○ Homologous to SDN-POA in rodents
● Patterns of cerebral asymmetry have been linked to sexual orientation in both men and
women
● Existence of neural differences does not prove that hormonal exposure caused the
difference
○ Brain is plastic and changes with experience
Summary of article 1
Concluding Remarks
● Many sex differences have been described in the human brain but onluy a subset have
been related to behavioral sex differences and fewer to the early hormone environment
● Toys have non-obvious properties that make them more or less attractive to an
androgen-exposed brain
Background of old, bad study (discredited)
Study Background
● Participants in study
○ Healthy controls
○ CAH
○ Diabetes
○ Siblings of CAH children
● Given the Sophia test in which they were asked to draw a person to answer the
question: if I could have chosen between being born a girl or a boy I would have
chosen…”
● Parents were interviewed about psychosexual and psychosocial development
● Other medical data were also collected
Results/conclusions of old bad study
Results/Conclusions
● Girls with CAH or diabetes scored more “on the boyish side” of the Sophia test
○ The effect on gender role behavior is not necessarily explained by hormonal
action alone; being sick plays a role
● CAH girls scored “on the more boyish side” than diabetic girls
○ Specific CAH effect is fully accounted for by the group of girls with the salt-loss
variant of CAH
● Degree of virilization does not correlate with gender score
● CAH and diabetic boys score “on the more girlish” side of the Sophia test
● Chronically ill children seem to have more problems with aggressive behavior than
healthy children
○ Diabetic girls differ from control girls in their appreciation of fighting
○ CAH boys and diabetic boys differ in their appreciation for “romping with father”
● Study suggests that activation of aggression is related to sickness rather than prenatal
hormonal factors
● The hypothesis that behavior is masculinized by exposure to androgen hormones cannot
be supported by this study
● Psychosocial factors such as the child being sick, and parents’ doubts about the sex of
the child seem to havre more influence on gender role behavior than does androgenic
hormone action
What we knew before article 3 about sex behavior
In human females, sexual responsiveness does not have the sharp relationship to
folliculogenesis and to the functioning of the corpus luteum in the ovary that us does in
most lower mammals
● In males of several species including humans, sexual activity persists following
castration
○ Corresponding phenomenon in females is encountered rarely in females below
the primates
● Female guinea pigs: the beginning of the preovulatory growth phase of the Graafian
follicle coincides closely with the beginning of being in heat
● Progesterone’s synergic action in combination with estrogens bring latent mating
behavior to expression
○ Has been demonstrated in numerous mammalian species
● Luteotrophin is responsible for the production of progesterone
Importance of Soma
● The nature of latent behavior brought to expression by gonadal hormones depends
largely on the character of the soma or substrate on which the hormones act
● Substrate assumed to be neural
Factors influencing character of soma
● Reports of the effects of thyroid hormone on the vigor of sexual behavior in the male are
very contradictory
● Sexual behavior is not inherited as a unitary trait
● Psychological factors might have a role in the determination of the character of the soma
● Males raised in isolation displayed an inability to mount a female properly
○ Guinea pigs need contact with other animals for the maturation of normal
behavior
Special influence of early hormonal factors
● Female guinea pigs given testosterone prenatally had ovaries and 2 sets of duct
systems
○ Also displayed male-typical behaviors
○ Lost ability to come into heat
● During the fetal period the hormones have an organizing action on the neural tissues
destined to mediate mating behavior in adulthood
● During the fetal period, gonadal hormones influence direction of differentiation and
during adulthood, they stimulate dunctioning
● In females and castrated males, development of the Mullerian system and regression of
the Wolffian system occurs
● Males castrated earlier in life and given estradiol and progesterone injections displayed
more female-typical behaviors than males castrated later
○ Castration after day 10 did not promote the development of female-typical
behaviors
Extension to sex-related behavior
● Study with monkeys
○ Female pseudohermaphrodites: a number of social behaviors known to be
sexually dimorphic and without any immediate instrumentality relative to mating
were influenced in the masculine direction
Implications of paper 3
● The principles of hormonal action in affecting sexual differentiation of the developing
brain provide a model to which we can look for a reexamination of psychosexual
incongruencies
● Testosterone does not induce masculinization of the adult female guinea pig while it’s
pregnant
Summary
● Hormones act according to principles which appear to be identical with those operative
during the differentiation of the genital tracts, and they affect a corresponding
differentiation or organization of neural tissues
● Early hormonal action is responsible for sex-related behavior which is part of the
masculinity or femininity of an individual but which is not related directly to the
reproductive process
