Gender: The role of chromosomes and hormones in sex and gender

Question 1

Make 3 points about typical chromosome patterns

Answer 1

-humans have 46 chromosomes arranged in 23 pairs
-the 23rd pair determines biological sex (XX or XY)
-genes are short sections of DNA that determine the characteristics of a living thing

Question 2

What chromosome do all cells produced by the ovaries have?

What about males (sperm cells)?

Answer 2

an X chromosome

50% carry an X chromosome and 50% carry a Y chromosome

Question 3

What determines the sex of a baby?

Answer 3

whether the sperm that fertilises the egg carries an X or Y chromosome

(if its X , baby will be female , if its Y the baby will be male)

Question 4

Make 1 point about male and female embryos in the first 8 weeks of development

Answer 4

they are identical and can generate either a male or female reproductive system

Question 5

What gene does the Y chromosome carry?

At about 8 weeks , what does this gene do?

Answer 5

SRY ( Sex-determining Region Y)

it instructs the XY embryo to release male hormones(androgens) which leads to development of testes/penis , otherwise the embryo develops a female reproductive system

Question 6

Make 4 points about the influence of hormones on sex and gender

Answer 6

-chromosomes initially determine sex , but gender development is influenced by hormones

prenatally-influences development of reproductive organs and brain development
puberty-influences secondary sexual characteristics

males and females produce the same hormones but in different concentrations

Question 7

Name the 3 hormones that play a bid role in gender development

Answer 7

testosterone
oestrogen
oxytocin

Question 8

Make 2 points about testosterone( what is it/where is it produced)

Answer 8

-its a male hormone that controls development of male sex organs
-mainly developed in the testes , small amounts are produced in the ovaries

Question 9

Make 3 points about testosterone , regarding what it acts on/creates etc

Answer 9

-it acts on the hypothalamus , creating a sexually dimorphic nucleus , which is larger in males than females
-without this the brain would develop in female form prenatally
-this is positively correlated with aggressive behaviour and negatively correlated with verbal ability

Question 10

Make 3 points about oestrogen (is it male/female , where is it produced and what does it do?)

Answer 10

-its a female hormone
-its produced in the ovaries and controls development of female sex organs and menstruation
-also produced in the testes and controls sperm production

Question 11

What are high levels of oestrogen associated with?

Answer 11

emotionality and irritability during the menstrual cycle

Question 12

Make 4 points about oxytocin

Answer 12

-its produced by the hypothalamus
-its produced in large amounts when women give birth and stimulates lactation
-it reduces levels of stress hormone cortisol and encourages bonding with baby
-males and females produce equal quantities during amarous activities

Question 13

Make 1 point about the effect of under/over exposure to hormones during prenatal development

Answer 13

it can lead to intersex conditions

Question 14

Name and describe the 2 intersex conditions

Answer 14

Androgen insensitivity syndrome-a genetic male is exposed to too little testosterone so develops female characteristics

Congenital Adrenal Hyperplasia-a genetic female is exposed to too much testosterone so has ambiguous genitalia

Question 15

Give 3 pieces of supporting evidence for the role of chromosomes and hormones in gender development

Answer 15

+ case study of David Reimer , suggested chromosomal influence is more important than environment as despite being raised as a female he still wanted to be male

+evidence support from animal studies:
Nanne van der Poll et al (1988)-showed female rats who were injected with testosterone became more masculine in behaviour(more physically and sexually aggressive)

Alexander and Hines (2002)-found vervet monkeys showed sex differences in toy preferences(males-car , females-doll)

Question 16

Give a general however point for all the pieces of supporting evidence

Answer 16

-the use of case studies and animal research makes it difficult to extrapolate findings to humans/generalise to all people

Question 17

Who provides contradictory evidence for the role of hormones and chromosomes in sex and gender?

Answer 17

-Eliot et al (2021)
did a meta analysis questioning previous findings and data showed male and female brains were overwhelmingly similar , any diffs in brains were small and inconsistent once individual brain sizes were accounted for

this questions the role of chromosomes and hormones in gender development

Question 18

Give another strength and weakness for the role of chromosomes and hormones in sex and gender

Answer 18

+practical apps , the International Olympics Committee used to conduct chromosome based gender verification tests until 2000 which suggests chromosomes and hormone do have a role in gender and sex

-other explanations , such as the SLT which states that children acquire their gender identity and associated gender appropriate behaviours through observation of others and direct reinforcement , suggesting chromosomes and hormones can’t be used in isolation to explain gender and sex