About __% men ___% women consider themselves straight
90% men. 85% women
__X as many bi F as males
Why bisexuality more common in female than male?
bisexuality is a transition stage for men.
___% men and ___% women are homo
4% men, 2% women
Non biological theories of sexual orientation
1. Psychoanalytic theories 2. Behaviorism/socialization 3. Effect of sexual experience 4. Social constructionism
Freud thought that family dynamics influenced sexual orientation
learning theorist suggest that gendered traits emerge from conscious or unconsciousness training imposed by parents and others.
Effect of sexual experience theory
early sexual experience influences sexual orientation
a person's identity as gay, straight, or bisexual is a label imposed by society and internalized by the individual.
Biological theories of sex orientation suggest that
1. S.O is determined or influenced by bio factors like genes and hormones 2. SO is a gendered trait, so men supposed to like women. 3. Homosexual people are sex atypical w/ respect to sex orientation as part of larger constellation of gendered traits.
In 1991 vs. 2009, space in textbooks devoted to non bio theories of SO vs. bio
bio theories were not prevalent in earlier times. Now they are getting lots of space devoted to them.
Men born gay = Women born gay
Men born gay - probably. Women? Possibly
Fruit fly experiment
1 gene called Fru, when knocked out caused flies to be homo
Genes often passed down ___in families
in maternal line
S.O. genes are ___ chromosome linked
Ben and Jerry are monozygotic twins - if Jerry is gay, what percent Ben is?
52%, not 100% due to environment
Fraternal twins - one twin gay, probability that other will be ?
likelihood that if one twin is gay, his or her cotwin will be gay too.
What advantages to having gay gene??
KIN SELECTION! - 2. Negative effect on one chromosome, but positive on other - he would be more feminine, less aggressive more caring - might have greater reproductive success if women like him 3.
A gene for sexual attraction to men would cause homosexuality in men but in women
might cause hyper heterosexuality - thus increasing reproductive success and passing the gene down.
***Prenatal hormone theory of homosexuality
1. Prenatal testosterone levels "organize" brain sex for later activation at puberty. 2. Adult sex hormone levels are normal. 3. Idea that women with more than normal testosterone are gay, guys with less than normal testosterone are gay. Testosterone ultimately alters the hypothalamus. High testosterone in prenatal environment of girl can cause CAH.
Effect of stress on prenatal hormones
stress lowers aromatase levels, which convert testosterone into estradiol. Increasing likelihood male baby will be gay b/c less estradiol to masculinize the developing male brain
Which trimester is most important in determining homosexuality
Finger length ratios
index/ring - straight women have highest, lesbos a little lower. straight and gay men no difference.
Third institial nucleus of the anterior hypothalamus
Men have bigger INAH-3, smaller in gay men compared to men.
2x larger in homosexual males
Right hemisphere compared between gays and straight
Right hemisphere is about 2% larger than left in straight men and lesbos
Straight women and gay men brain
two hemispheres are the same in gay men and women
Auditory otoacoustic emissions
sounds given off by ear in response to hearing a sound
Auditory otoacoustic emissions in females and males
Straight f gives most. Lesbos sig less. Men give more than gay men, both men lower than homo f. Femal-homofem-men-gaymen
men and lesbos better at suppressing it than straight females
Brain activation sex pheromones AND and EST
Est activates male hypothalamus. AND activates the female and GAY MALE hypothalamus.
Men better at darts than women, what about gays
gay male bad like women. lesbos almost good as straight males.
Gay males and female have high. Lesbos and Smales have lower
Gay men are reported to be less/more physically aggressive than straight men
Lesbians are reported to be less/more aggressive than straight women
_____ is the best predictor of later homosexuality
early gender non conformity
___ have more older brothers on avg than straight men
Gay males have more older brothers on avg than straight, why?
maybe some women develop antibodies to male specific antibodies during early pregnancies with male fetuses - increases likelihood of homosex.