Sexual Orientation

1
Sexual Orientation
2
Myth?

• Lesbians and gays are always trying to seduce
  heterosexuals.
• Gays and lesbians are oversexed.
• Bisexual have the best of both worlds.
• Its easy to spot a gay or lesbian in a crowd.
• Within a relationship setting, gays and lesbians
  mimic traditional heterosexual patterns.

3
Sex Typical Behavior

• Do gay men prefer feminine males? Lesbians prefer
  masculine females?
• Both gay men and lesbians tend to prefer
  sex-typical appearance
• preference less strong for feminine males
• no typical preference for sex-typical behavior
  among lesbians
• (Bailey et al., 1997)

4
Prevalence

• Alfred Kinsey (1953)
• exclusively heterosexual
• 75-85 males
• 80-90 females
• exclusively homosexual
• 4 males
• 2 females
• bisexual
• 10-15 males
• 8-10 females
• More recent studies have replicated these rates

5
Homosexuality as a Mental Illness

• DSM (1952) sociopathic personality disturbance
• DSM-R (1968) sexual deviation
• DSM-II (1973) ego-dystonic homosexuality
• Criteria for mental disorders
• causes personal distress
• interferes with social effectiveness
• DSM-III and beyond

6
Psychopathology

• (Fergusson et al., 1999)

7
Genetic Evidence

• Family studies
• homosexual females more likely to have homosexual
  brothers (Bailey Bell, 1993)
• brothers concordant for homosexuality were
  similar in childhood gender nonconformity
  (Bailey, 2000)
• gender nonconformity inherited trait for both
  males and females
• 90 of gay or bisexual males had sons who were
  straight (Bailey, 1995).

8
Genetic Evidence

• Twin studies
• 52 concordance identical twins (male)
• 22 concordance fraternal twins (male)
• 11 concordance for genetically unrelated
  brothers (Bailey Pillard, 1991)

9
Genetic Evidence

• Sex - linked?
• X-linked
• Xq28 region
• Some studies indicate homosexuality on both
  maternal and paternal sides (Bailey et al., 1999)

10
Brain Anatomy Evidence

• Hypothalamic differences
• suprachiasmatic nucleus (SCN) larger and has more
  cells in gay men (Swaab, 1990)
• INAH1-4 regions (Simon LeVay, 1991)
• examined homosexual men, heterosexual men and
  women
• area INAH3 differentiated groups

11
Hormone Prenatal Evidence

• Prenatal
• exogenous hormone administration
• DES
• H-Y antigen
• maternal stress
• testosterone levels
• handedness
• otoacoustic emissions (OAEs)
• finger lengths, 2d4d
• Testosterone levels in adulthood

12
Birth Order

• Latter born sons more likely to be gay
• Mothers develop immunity to H-Y Antigen
• (Blanchard, 2001)

13
Behavioral Measures

• Gay men on average better at spatial rotation
  than gay women
• Gay men more aggressive and competitive than gay
  women
• Straight men more aggressive and competitive than
  gay men

14
Homosexuality Evolution

• How can a trait that seems to inhibit the
  likelihood of offspring remain in the population?

15
Homosexuality Evolution

• balanced polymorphism
• biological exuberance
• reciprocal altruism - same sex alliances
• kin-selection
• (Miller, 2000)

16
Sex Differences inSexual Orientation

• Is it a phase?
• Men - hard wired
• Lesbian and bisexual young women were followed
  over a 5 year period (Diamond, 2003)
• Over a quarter relinquished their gay identity
• More likely to indicate attraction to both men
  and women
• indicated that degree of attraction to men and
  women did not significantly Change
• 1 women described lesbian period as a phase

17
Sex Differences inSexual Orientation

• Sex differences in sexual arousal patterns
  (Chivers et al., in press)
• examined gay and straight men and women, and male
  to female transsexuals
• viewed male/male, female/female, and male/female
  erotica
• gathered physiological and subjective data

18
Legal Issues

• Antisodomy laws

19
Antisodomy Laws

• Sec. 21.01. Definitions.
• (1) "Deviate sexual intercourse" means
• (A) any contact between any part of the genitals
  of one person and the mouth or anus of another
  person or
• (B) the penetration of the genitals or the anus
  of another person with an object.
• Sec. 21.06. Homosexual Conduct.
• (a) A person commits an offense if he engages in
  deviate sexual intercourse with another
  individual of the same sex.
• (b) An offense under this section is a Class C
  misdemeanor. (500)

20
Legal Issues

• Antisodomy laws
• Gay parents gay adoption

21
Gay Parents Children of Gay Parents

• Comparing gay and straight parents (e.g., Allen
  Burrell, 1996).
• Parental data
• parents rating of parent/child interaction
• parental attitude about sexual development
• rating of childs level of satisfaction
• teachers rating of childs school behavior
• Child data
• sexual orientation
• life satisfaction
• cognitive development

22
Gay Parents Children of Gay Parents

• Children of gay parents highly likely to report
  that their problems are related to their parent
  being gay (94)(Cameron Cameron, 2002)
• Children of gay parents equally likely to be
  teased, but teased about family (e.g.,
  Vanfraussen et al., 2002)

23
Gay Adoption

• Do adoption agencies allow gay adoption?
• 823 adoption agencies contacted, 26 responded
  (Brodzinsky et al., 2002)
• of these
• 63 accepted applications from gay couples
• 38 had made at least one gay adoption

24
Legal Issues

• Antisodomy laws
• Gay parents gay adoption
• Gay marriage