Chapter 10: Reproduction/ Sexual Behavior

Question 1

Hormones

Answer 1

● Secreted by endocrine glands through the blood
○ Bind to receptors on cell walls or bind inside the cell
○ Coordinate long lasting changes

Question 2

Steroid hormones

Answer 2

made from cholesterol (example: cortisol)

Question 3

Sex steroids

Answer 3

released by testes and ovaries
■ Activate sex-limited genes

Question 4

Sex steroids

Answer 4

Types:
● androgens (higher in males) includes testosterone
● Estrogen (higher in females) includes estradiol
○ Estradiol is a metabolite of testosterone, ingesting large
amounts of testosterone will cause body to convert
testosterone to estradiol= female typical body parts
(breasts)

Question 5

Gonads

Answer 5

hormones not needed for development

Question 6

Gonads

Answer 6

○ Bipotential in early embryo (4-6 weeks)
○ SRY gene on Y chromosome = testes
○ Absence of gene= ovaries

Question 7

Internal sex organs

Answer 7

bipotential until 3 months

Question 8

Mullerian ducts

Answer 8

need no hormones to develop
■ Fallopian tubes, uterus, cervix

Question 9

Wolffian ducts

Answer 9

needs hormones to develop
■ Epididymis, vas deferens, seminal vesicle

Question 10

MIH from testes

Answer 10

inhibits Mullerian system
○ Notes: prostate is separate

Question 11

External sex organs

Answer 11

bipotential until 7-8 weeks
○ Penis, scrotum= hormones required
○ Vagina (outer), labia, clitoris= hormones not needed

Question 12

Issues of Non-Heterosexuality

Answer 12

● Alfred Kinsey (1947): 10% Americans were gay

Question 13

Issues of Non-Heterosexuality

Answer 13

● More recent surveys by Indiana University, Kinsey Institute
○ 4% men are exclusively homosexual and 3% women
■ 1% exclusively bisexual

Question 14

Issues of Non-Heterosexuality

Answer 14

● 2016 exit poll
○ 5% identified as gay, lesbian, bisexual, pansexual (non-heterosexual)
● Boggaert survey: 1% identify as asexual
● Millennials: 4% bisexual, 2% gay, 1% lesbian, 1% transgender
● Gallup poll (2022): 7.3% identified as non-heterosexual

Question 15

Testosterone Levels (causes of sexual orientation)

Answer 15

circulating amount as an adult does not predict sexual orientation
○ Timing of exposure to testosterone (especially in utero) may impact

Question 16

Genetic Studies (causes of sexual orientation)

Answer 16

assumes there is a genetic component
○ (studies conducted on gay men, but results similar for lesbains)
○ Twin studies: Identical twins have a 52% concordance rate
■ If one twin is gay, 52% chance the other will be gay as well

Question 17

Genetic Studies (causes of sexual orientation)

Answer 17

○ Fraternal twins have 22% concordance rate
○ Adopted brothers have 11% concordance rate
○ If homosexuality is genetic, how are the genes passed down for it?
■ Non concordant straight twin has higher than average sex partners

Question 18

Hypothalamus (neuroanatomical differences)

Answer 18

■ Simon Levary 1991 cadaver study: included…
● 19 homosexual men all died from AIDS
● 16 hetero men with 6 died from AIDS
● 6 hetero women

Question 19

Hypothalamus (neuroanatomical differences)

Answer 19

■ Found sexually dimorphic nucleus (SDN) was ½ the size in gay compared to straight men
● Gay men had the same size SDN as heterosexual women

Question 20

Hypothalamus (neuroanatomical differences)

Answer 20

■ Cannot establish cause and effect, study is correlational