Gender: The role of chromosomes and hormones in sex and gender Flashcards
Make 3 points about typical chromosome patterns
-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
What chromosome do all cells produced by the ovaries have?
What about males (sperm cells)?
an X chromosome
50% carry an X chromosome and 50% carry a Y chromosome
What determines the sex of a baby?
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)
Make 1 point about male and female embryos in the first 8 weeks of development
they are identical and can generate either a male or female reproductive system
What gene does the Y chromosome carry?
At about 8 weeks , what does this gene do?
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
Make 4 points about the influence of hormones on sex and gender
-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
Name the 3 hormones that play a big role in gender development
testosterone
oestrogen
oxytocin
Make 2 points about testosterone( what is it/where is it produced)
-its a male hormone that controls development of male sex organs
-mainly developed in the testes , small amounts are produced in the ovaries
Make 3 points about testosterone , regarding what it acts on/creates etc
-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
Make 3 points about oestrogen (is it male/female , where is it produced and what does it do?)
-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
What are high levels of oestrogen associated with?
emotionality and irritability during the menstrual cycle
Make 4 points about oxytocin
-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
Make 1 point about the effect of under/over exposure to hormones during prenatal development
it can lead to intersex conditions
Name and describe the 2 intersex conditions
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
Give 3 pieces of supporting evidence for the role of chromosomes and hormones in gender development
+ 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)
Give a general however point for all the pieces of supporting evidence
-the use of case studies and animal research makes it difficult to extrapolate findings to humans/generalise to all people
Who provides contradictory evidence for the role of hormones and chromosomes in sex and gender?
-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
Give another strength and weakness for the role of chromosomes and hormones in sex and gender
+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
