4 Female Male Chromosomal Intersex

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Part 4 of "Science & Sexuality." What exactly is a female? a male? an intersex person? Some kinds of intersex people are chromosomal variants. What can we learn about sexual identity and sexual …

Part 4 of "Science & Sexuality." What exactly is a female? a male? an intersex person? Some kinds of intersex people are chromosomal variants. What can we learn about sexual identity and sexual orientation from sex chromosomal variants? Who is Milton Diamond? John Money?

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  • 1. What Is a Female? A Male?
    • Primary sex characteristic
      • Type of gonads
        • Female gonad is ovary – produces eggs
        • Male gonad is testis – produces sperm
      • Develop in fetus
      • Testosterone & its derivatives are “directional”
    • Secondary sex characteristics
      • Produced by gonadal hormones
        • Androgens
        • Estrogens
      • Develop during puberty
      • Hormones are “activational”
  • 2. Sex Has Many Levels
    • Genetic Sex - Chromosomes
    • Gonadal Sex – Ovaries or Testis
    • Somatic Sex – Body anatomy/physiology
    • Psychological Sex - Sexual identity
    • and then there is
    • Sexual orientation
  • 3. Intersexuality
    • Incidence: 1.7%*- 2.5%
    • Intersexual people are as natural as the rest of us
    • They are nature’s experiments to a physiologist – providing information about sexual development
    • Only in recent years have we been able to track intersexual people over their lifetime and find out about their sexual identity and orientation
    • They illustrate how no definition of female or male is always “satisfying”
    • * Fausto-Sterling, Anne. SEXING THE BODY: GENDER POLITICS AND THE CONSTRUCTION OF SEXUALITY. Basic Books (2000)
  • 4. Ganong, William F. REVIEW OF MEDICAL PHYSIOLOGY 22 nd ed. Lange Medical Books/McGraw-Hill (2005)
  • 5. How to Treat a Newborn With Ambiguous Genitalia or Mutilated Penis?
  • 6. John Money Psychologist
    • Psychosexual "neutrality-at-birth" theory
      • Postulate 1: Individuals are psychosexually neutral at birth
      • Postulate 2: Healthy psychosexual development is intimately related to the appearance of the genitals
  • 7. Milton Diamond Biologist
    • “ Sexuality-at-birth" theory
      • Theory of psychosexual predisposition
      • Inherent sexuality provides a built-in "bias" with which the individual interacts with his environment
      • Prenatal genetic and hormonal influences predispose at birth to a male or female gender orientation
      • Sexual behavior of an individual, and thus gender role, are not neutral and without initial direction at birth
    • Diamond challenges Money
    • Diamond M. A Critical Evaluation Of The Ontogeny Of Human Sexual Behavior. QUARTERLY REVIEW OF BIOLOGY, 40: 147–175 (1965)
    • The John / Joan case
    • Diamond, Milton. And Sigmundson, H. Keith. Sex Reassignment at Birth: A Long Term Review and Clinical Implications. ARCHIVES OF PEDIATRIC & ADOLESCENT MEDICINE, 151: 298-304 (1997)
    • Money’s view is now discredited!
  • 8. Chromosomal Variants of Sexes 1/500 of the population have a karyotype other than XX or XY. Intersex Support Group International (1999-2001) Ganong, William F. REVIEW OF MEDICAL PHYSIOLOGY 22 nd ed. Lange Medical Books/McGraw-Hill (2005)
  • 9. Variations of Genetic Sexes
    • Nondisjunction of chromosomes
      • XO Female (Turner Female)
      • XXX Female (Superfemale)
      • XXY, XXXY etc. Male (Klinefelter Male)
      • XYY Male (Jacob’s Syndrome)
    • Translocation of SRY gene from Y to X chromosome
      • XY Female (Swyer syndrome): absence or mutation of SRY on Y produces females with gonadal dysgenesis
      • XX Male (XX Male Syndrome): SRY gene in one or both X chromosomes, produces infertile males
  • 10. Turner’s Syndrome
    • Karyotype is 44 autosomes plus XO
    • Ovarian agenesis or gonadal dysgenesis
      • Gonads rudimentary or absent
      • Female external genitalia
      • Short stature, other congenital abnormalities
      • No maturation at puberty
    Luria, Z., Friedman, S., and Rose, M.D. HUMAN SEXUALITY. New York: John Wiley & Sons (1987)
  • 11. Turner’s  Syndrome Forbes, C.D. and Jackson, W.F. A COLOUR ATLAS AND TEXT OF CLINICAL MEDICINE. England: Mosby-Wolfe (1993)
  • 12. Klinefelter Syndrome
    • Karyotype 47XXY
    • Most common sex chromosome disorder (1 or 2 cases/1000)
    • Male phenotype
    • Hypogonadism
    • Seminiferous tubule dysgenesis
      • Reduced or absent spermatogenesis
      • Variability in presentation is related mainly to the timing and amount of androgen deficiency
      • Increased FSH levels (indicates low inhibin B from Sertoli cells)
      • The more supernumerary sex chromosomes that exist, the more likely are detrimental physical and mental findings
      • Cryptorchidism 3X more frequent
      • Taller, greater leg growth ( 5 and 8 years)
      • Tendency for central obesity
      • Minority born with small penises; testosterone cream caused penis growth; however, normal size penis in only 77% by end of puberty; in contrast, testes normal size at birth but fail to grow normally
      • Gynecomastia 30% to 90% of cases
      • May have diminished body and facial hair, female pubic hair pattern, small phallus, poor muscular development, and progressive disproportion in leg and body length, feminine fat distribution
      • Fertility becomes increasingly doubtful as age advances; however, before infertility is predicted, sperm analysis is required because paternity has been documented
    Forbes, C.D. and Jackson, W.F. A COLOUR ATLAS AND TEXT OF CLINICAL MEDICINE. England: Mosby-Wolfe (1993)
  • 13. Klinefelter Syndrome & Gender Expression
    • Infrequently discussed in medical descriptions of KS are individuals’ concerns with gender expressions and feelings
    • An unknown percentage of persons who have KS experience androgynous or feminine feelings that can develop at an early age
    • Some people who have KS consider themselves to be transgendered , others intersexed, and others transsexual; in one study, investigators concluded that all of their KS patients viewed their personalities as dual male and female
      • A host of investigators similarly reported cases of men who had KS who transitioned to live as women or who harbored aspects of gender dysphoria
      • Carolyn Cossey, a “James Bond girl,” was raised as boy, but changed to live as a girl at young age, and became a famous model; her karyotype was found to be XXXY
  • 14. KS Subjects Are Gynephilic!
    • KS subjects are gynephilic!  ”Homosexuality” among KS males was not found or the prevalence was not any different from that seen in the general population ( Shirley Ratcli ff e Arch Dis Child 1999; 80 :192–195)
    • Note: This indicates that sexual orientation region(s) of brain have been “altered.” Significantly, XXY fetal prenatal and postnatal testosterone levels do not differ from XY controls – so testosterone is available to “alter” hypothalamic and other brain regions during development of KS brain
  • 15. Comparison of XYYs and XXYs Sex Roles
    • Similarities far outweigh the differences except for sex roles
    • XXY has more problems with masculine role
      • Appear less masculine
      • More submissive and dependent
      • Drawings show less sex-differentiation
      • Ratcliffe, Shirley. Long Term Outcome In Children Of Sex Chromosome Abnormalities. ARCH DIS CHILD; 80:192–195 (1999)
  • 16. Why Do Many of These KS “Men” Identify As Androgynous or Women?
    • My tentative answer
    • Research evidence for expression of genes on sex chromosomes in early brain development
    • XX and XY embryonic rodent brains develop differently before gonads develop (so hormone influence is not a factor)
    • Dewing, P., Shi, T., Horvath S., and Vilain, E. Sexually Dimorphic Gene Expression in Mouse Brain Precedes Gonadal Differentiation. MOLECULAR BRAIN RESEARCH, 118: 82-90 (2003)
    • Carruth, Laura L., Reisert, Ingrid, and Arnold, Arthur P. Sex Chromosome Genes Directly Affect Brain Sexual Differentiation. NATURE NEUROSCIENCE, 5: 933-934 (2002)