13.7 Sexual orientation and Gender Identity

Question 1

what is the concordance for homosexuality in mono and dizoogotic twins respectively? (males and females differ)

Answer 1

52 and 22 in males

48 and 16 in females

Question 2

is sexual orientation due to low levels of sex hormones? what two findings support this

Answer 2

no

1. no differences in avg levels of circulating hormones
2. orchidectomy reduces sex behaviour in both groups, doesn’t redirect it and replacement injections return previous dispoosition

Question 3

What is the consistent finding about perinatal hormones and sexual orientation?

Answer 3

not uncommon to see males engaged in female typical sexual behaviour and vice versa

Question 4

what occurs in perinatal castration of males?

Answer 4

increased preference for male sex partners as adults

Question 5

what occurs in cases of female prenatal exposure toT

Answer 5

increased preference as adults for females

Question 6

what are the two things to keep in mind about studies of sexual preferences on lab animals

Answer 6

1. lots of cognitive and emotional aspects of human sexuality that cannot be replicated
2. but too strong of a pattern to ignore it

Question 7

what is the evidence that perinatal hormones can influence sexuality

Answer 7

adult females exposed to diethylstilbestrol (synthetic estrogen) during pregnancy

• more sexually attracted to females than matched controls
• still relatively weak, only 1/30 of these ladies were homo

Question 8

what is the fraternal birth order effect

Answer 8

the probability of a male being gay increases as a function of the number of brothers he has

• only related to number of brothers born to a mother
• large effect, 33.3% increase for every older brother

Question 9

what is the maternal immune hypothesis?

Answer 9

proposed explanation of the fraternal birth order effect
- some mothers may become progressively more immune to masculinizing hormones inn male fetuses, and her immune system might deactivate masculinizing hormones in younger sonns

Question 10

when do most ppl in the west experience their first feelings of sexual attraction? when do they hit puberty?

Answer 10

10,

10.5 for girls, 11.5 for boys

Question 11

Explain McClintock and Herdt’s suggestion for what stimulates sexual attraction

Answer 11

may be stimulated by adrenal cortex steroids, unlike gonadal maturation, adrenal maturation occurs at 10

Question 12

explain the LeVay findings about brain differences between heterosexuals and gay people

Answer 12

structure of a hypothalamic nucleus in gay males was intermediate between female and male heterosexuals

• not consistently replicated
• no reliable difference has been isolated

Question 13

What is Transsexualism

Answer 13

condition where a gender identity is inconsistent with anatomical sex

Question 14

what is the process of male to female sexual reassignment

Answer 14

1. establish that the person is a good candidate - in dept counselling
2. estrogen administration - feminize the body, hormone reginmen continues for life
3. penis and testes are removed
4. female external genitals and vagina are constructed
5. vagina is linked with skin and nerves from the former penis so it will have sexual sensation
6. sometimes have cosmetic surgery to feminize the face (decrease Adams apple)

Question 15

what was the initial assumption about the cause for transexualism? was it right? what is it really?

Answer 15

produced from atypical child rearing practices

• nope, although there are cases that are consistent with this
• we dont know!

Question 16

what is a major difficulty preventing further study about the causes of transsexualism?

Answer 16

doesn’t happen in other species