The role of chromosomes and hormones Flashcards
What does the biological perspective suggest about gender?
Behavioural, psychological and social differences between genders are seen to be the result of anatomical, chromosomal and hormonal differences.
What does chromosomes carry?
The Y chromosome carries a sex-determining region Y gene which produces androgens
What are androgens?
- Help start puberty and play a role in reproductive health and body development
- All genders make androgens but males make more of them
- Testosterone is the most common androgen
What is oxytocin?
- Hormone stimulates lactation and is often referred to as the ‘love hormone’ (both m/f)
- facilitates bonding
- Reduces stress hormone cortisol
- linked to less interest in intimacy/ closeness in relationship and less nurturing fathers in men
What does oestrogen do?
heightens emotions and irritability during mensturation
Where is the SRY gene found?
On the Y chromosome
What does the SRY gene make?
SRY protein
What is the SRY protein?
- Sex determining region on the Y chromosome
- involved in male-typical sex development
What does SRY gene/protein cause?
Androgens (testosterone) to be released in the womb at 7 weeks
What does the SRY gene/protein also act on?
Also acts on the hypothalamus and masculinises the brain
What area of the hypothalamus is larger in males than females?
Sexually dimorphic nucleus
What is sexual dimporhism?
The condition where sexes of the same species exhibit different morphological (internal structures; brain structures) characteristics
What is congenital adrenal hyperplasia?
- Rare genetic disorder that cause high pre natal levels of male hormones such as testosterone
- can occur in both females and males
Why is congenital adrenal hyperplasia more obvious in women?
Because of the masculinising effects of male hormones - may have ambiguous genitalia.
What did Berenbaun and Bailey (2003) find?
Found females with CAH often described by friends and family as tomboys and exhibit larger levels of aggression, show preference
What does CAH suggest?
Suggests that hormones have a powerful influence on gender and gender related behaviour.
However what does girls with CAH suggest?
- Girls with CAH show more masculine behaviour because they look like boys, rather than because of testosterone.
- Therefore it may not be sound evidence for biological cause of behaviour it may be due to their experience and socialisations
- Also low sample sizes means the generalisability to wider populations may be inappropriate.
A03 Supporting evidence for the biological explanation for sex and gender comes from the case study on David Reimar
- John Money argued that sex of rearing was much more important and recommended that intersex individuals such as Reimar could be raised as either boy or girl
- Initially study supported his views but David showed a strong male identity
- Further supported by Reiner and Gearhart who studied 16 males with almost no penis
- 2 raised as males, rest as females.
- 8 reassigned themselves as males by age of 16
- Therefore supports a biological explanation for sex and gender, as it suggests that gender is influenced by individuals sex chromosomes
A03 With this being said gender is not soley determined by chromosomes and hormone; other factors have been found important too.
- for example, CAH occurs when females (XX0 have prenatally high levels of male hormones resulting in varying degrees of external male genitalia
- Research show that whatever gender assigned at birth is accepted by some
- Suggests that the eventual outcomes for individuals appears to be a complex and unpredictable combination of genes, hormones, sex-rearing and socialisation
- bio view does not accurately reflect complexity of gender development
A03 Supporting evidence for the role of testosterone
- Comes from experimental research with non human animals
- Quadagno et al (1977) found female monkeys who exposed to testosterone during prenatal development later played with more rough and tumble play than other females
- supports the view that pre-natal exposure to androgens can influence more masculine behaviour supporting the hormonal explanation
A03 with this being said there are issues generalising from non-human animal studies because human behaviour is governed (to some extent) by expectations and deliberate choice
- Eisnegger et al (2010) observed women playing a bargaining game
- Those who believed they were given a dose of testosterone behaved in a more unfair manner than those who believed they were given a neutral placebo
- thereby demonstrating the effect of expectations
- suggests that hormones may influence brain development and human behaviour, but the relationship is not a simple one
A03 Furthermore, there is conflicting evidence regarding the role of testosterone in gender behaviour such as aggression.
- In a double-blind, placebo study O’Conner et al (2014) increased testosterone in healthy young men
- No increase in interactional (sexual intercourse) or non-interactional (sex drive) components of sexual behaviour in ppts
- Also experienced no change in aggression
- Suggests that additional T have no effects on masculine traits such as sexual/aggressive behaviours
- Do need to acknowledge that this evidence does not challenge to role of testosterone in early development.
