Gender and Sexuality 3/11/24 HS2024 PDF

3/11/24 GENDER AND SEXUALITY 1 Prenatal Factors Infancy and Childhood Puberty Adult Gender Identity 2 1 3/11/24 Gender: Historical Prior to19th century: didn’t know, didn’t care, few case studies 1890’s: ‘True sex’ was based on gonads. If you had ovaries (no matter how masculine you looked) you were...

3/11/24 GENDER AND SEXUALITY 1 Prenatal Factors Infancy and Childhood Puberty Adult Gender Identity 2 1 3/11/24 Gender: Historical Prior to19th century: didn’t know, didn’t care, few case studies 1890’s: ‘True sex’ was based on gonads. If you had ovaries (no matter how masculine you looked) you were a woman 1910: biopsies conclusively show whether ovaries/testes are functional but people still classified as to what was most ‘believable’ 1950: Wilkins and Money advocate for ‘sex normalizing’ surgeries and hormonal treatment 3 Spectrum of Sexual Organ Variation 4 2 3/11/24 Biological Sex Variations Intersexed: a person who possesses both male and female biological traits. Genitalia may appear somewhere between a penis or vagina Term hermaphrodite is considered outdated, and inaccurate More common than realised. 2% of live births (Blackless et al., 2000) 5 Biological Sex Variations Congenital Adrenal Hyperplasia Swyer Syndrome Complete / Partial androgen insensitivity syndrome 5 alpha-reductase deficiency Turner’s syndrome Klinefelter’s syndrome 6 3 3/11/24 Biological Sexual Development 7 ~ 3 weeks: a primitive heart begins to drive blood through embryonic bloodstream 5 - 6 weeks: undifferentiated genitalia form 8 4 3/11/24 5 - 6 weeks after conception Each embryo (male/female) possesses: primitive external genitalia undifferentiated gonads, two sets of primitive ducts Mullerian / female) Wolffian / male) 9 Both sexes resemble primitive female structures during the first 6 weeks Default pathway of most fetal tissues in mammals is to develop in the female direction 10 5 3/11/24 ~7th week: genetic code (XX / XY) asserts itself 11 ~7th week: genetic code (XX / XY) asserts itself Activity on the Y chromosome causes the testes to begin to differentiate. If Y chromosome is absent the ovaries develop and begin in form LATER at 11-12 weeks 12 6 3/11/24 Fetal Gonads Mullerian Ducts embryonic structures that develop into female sexual and reproductive organs unless inhibited by male hormones Wolffian Ducts embryonic structures that develop into male sexual and reproductive organs if male hormones are present 13 Congenital Adrenal Hyperplasia Inherited recessive gene resulting in deficiency in the production of cortisol and the overproduction of adrenal androgens Between 9th - 13th week of gestation excessive androgens negatively effect the female fetus Genital ambiguity can result 14 7 3/11/24 Congenital Adrenal Hyperplasia CAH can occur in XX and XY. XY: physical and psychological development follows typical male pattern XX: become more physically and psychologically masculine. At birth, genitals appear partially or completely masculine, although internally, female gonads are present 15 Congenital Adrenal Hyperplasia 16 8 3/11/24 Congenital Adrenal Hyperplasia Masculinization of the female CAH psyche: interest in boys’ toys (e.g., vehicles, military accessories) and disinterest in girl toys (e.g, dolls) Drawings contain boy motifs (e.g., vehicles, mechanisms) rather than feminine (e.g., human, animals) During adolescence prefer male* activities (e.g., martial arts, angling, looking after motorcycle) 17 Congenital Adrenal Hyperplasia Masculinization of the female CAH psyche: Particularly good spatial ability (targeting, maze task) More likely to be bisexual Less interest in being mothers ~5% identify with being male 18 9 3/11/24 Congenital Adrenal Hyperplasia In terms of sexuality (CAH females): Most report attraction to men Some studies find higher rates of same-sex attraction and bisexual orientations (MeyerBahlburg et al, 2008) 19 Congenital Adrenal Hyperplasia Controversial treatment with dexamethasone potent synthetic steroid administered almost as soon as mother is pregnant* and before 7th week when humans start to differentiate into m/f 20 10 3/11/24 10 week Male 21 10 week Female 22 11 3/11/24 Biological Sexual Development Specific region on the Y chromosomes important for directing sexual development: SRY SRY gene: causes precursor cells in the embryo to develop into Sertoli cells (produce anti-Mullerian hormone) and Leydig cells (produce testosterone) which cause the gonads to develop into testes XY males lacking SRY develop as females (Swyer syndrome) XX with a misallocated SRY develop as males 23 Swyer Syndrome: XY lacking SRY complete 46, XY gonadal dysgenesis Genetic male (XY) Body does not respond to testosterone during development Hanne Gaby Odiele Possible genital female appearance at birth (but with undescended testes and unusually short vagina and no cervix) 24 12 3/11/24 Case Study 15 year old primary amenorrhea Prescribed Estrogen and Progestrone which she stopped taking Married at 15. Short than husband but at age 50 considerably taller 25 Complete Androgen Insensitivity Syndrome XY fetus insensitive to production of its own androgens Despite XY, body and genitals have feminine genital appearance Child appears typical female with shallow vagina. Usually not detected until puberty with a failure to menstruate or undescended testicle appears as a mass in the groin or abdomen 26 13 3/11/24 Complete Androgen Insensitivity Syndrome Usually raised as girls and adopt a female gender identity (Mazur, 2005) Most become sexually active and majority are attracted to men (Wisniewski et al.,2000). 27 Similarities/Differences Swyer Little or No breast development Testes are replaced by fibrous streaks that don’t secrete testosterone CAIS Normal breast development Testes are usually well formed and located in labia or abdomen Presence of testis-like masses in a phenotypically female patient before puberty suggests the diagnosis 28 14 3/11/24 Partial Androgen Insensitivity Syndrome XY male that partially responds to androgens Genitals appear to be a mix of male and female structures and not clearly identifiable Hypospadiasis (urethral opening on underside of corona) Can identify as male or female Sexual attraction is variable 29 5-Alpha-Reductase-Deficiency XY male foetus is unable to convert testosterone to dihydrotestosterone (DHT) due to insufficient levels of 5-alpha reductase enzyme. DHT is necessary for development of male external genital structures. 30 15 3/11/24 5-Alpha-Reductase-Deficiency Depending on the amount of feminisation they may appear completely female, a mix of male/female structures or incomplete male. Regardless external appearance male gonads are present internally 31 5-Alpha-Reductase-Deficiency Most 5-alphaRD babies raised as girls and adopt female gender identity during childhood But, upon reaching puberty, testosterone production results in masculinisation Testes descend, genital structures grow into small penis, secondary sex characteristics Most then switch to male gender identity (Mendonca, et al., 1996). Those that do, are typically attracted to women 32 16 3/11/24 Turner Syndrome (XO) Prevalence: 1/2,500 female births female genitalia Lack of ovaries, menstruation, pubic hair, breasts with widely spaced nipples Stunted growth Treatment includes growth hormones and hormonal replacement therapy Most identify as female 33 Dichotic Listening Task Most people have a left hemisphere dominance for verbal listening 34 17 3/11/24 Less likely to show a right ear advantage and more likely to show a left ear advantage. There right hemisphere becomes adapted to deal with language processing. This comes at a cost … 35 We need our right hemisphere for spatial and mathematical reasoning In Turner’s this hemisphere is already being used for verbal reasoning and therefore spatial, non-verbal abilities, suffer 36 18 3/11/24 37 38 19 3/11/24 Klinefelter Syndrome (XXY) frontal baldness 1/500 to 1/1000 births Male genitals but female secondary characteristics narrow shoulders Sometimes timid, withdrawn Sterile breast development little hair development Low sexual desire Most attracted to females but many do not identify as being male small testicles 39 Performance IQ Verbal IQ 40 20 3/11/24 True Affirmative Jim is Kicking Mary 41 False Affirmative Mary is Kicking Jim 42 21 3/11/24 False Negative Ann is not tickling Mike 43 True Negative Mike is not tickling Ann 44 22 3/11/24 left hemisphere dominance right hemisphere dominance High right hemisphere and low left hemisphere 45 Measuring hemispheric activation is unreliable in youth. Finger Print ridge count is highly objective though. 46 23 3/11/24 Finger Print Ridge Count Low Ridge Count associated with Klinefelter’s High Ridge Count associated with Turner’s Low ridge count signifies a slower cell division rate during gestation and results in a slower left hemisphere development Hence the language deficits in Klinefelter’s but not Turner’s 47 lower ridge count (Klinefelter’s, XXY) correlated with lower left hemisphere activation and greater right hemisphere activation 48 24 3/11/24 lower ridge count associated with worse verbal ability 49 Dr. C. Netley supported 30 years later with fMRI 50 25 3/11/24 Other Biological Sexual Developments …less common Supernumery Y Syndrome (XYY) Appearance of normal male Tend to be taller stature Some lack of control over impulses Usually average intelligence 51 Other Biological Sexual Developments …less common Triple X Syndrome (XXX) Appearance of normal female Sometimes infertile Occasional intellectual impairment 52 26 3/11/24 Biological Sexual Development Possible Hermaphrodite (XX/XY) Variable. Combination of ovarian and testicular tissue Usually have a uterus At puberty most experience breast enlargement and majority menstruate 53 Biological Variations and Gender Identity Note the importance of pre-natal exposure to hormones For both 5-alphaRD and AIS we have XY males who do not get the full androgen exposure. But in… AIS - result is a female identity 5-alphaRD - result is a male identity CAH in women and tendency toward more masculine traits 54 27