The Role of Chromosomes & Hormones 1

• (AO1) Give the intro

  The possible role of chromosomes in sex and gender development considers how relevant characteristics and traits develop as a result of genetics, the brain, and hormones.

  
  

  This explanation proposes that gender is not solely learned but is influenced by physiology.
• (AO1) What is the typical chromosome pattern for 23rd pair? State the role of the Y chromosome

  The typical chromosome pattern for 23rd pair is XY in males, and XX in females, occurring at conception.

  
  

  The Y chromosome houses the SRY gene - this determines the development of the testes, which produces testosterone.
• (AO1) Role of oxytocin in sex and gender

  Females are typically associated with nurturing characteristics.

  (1) The pituitary (master) gland releases a second hormone - posterior, which produces oxytocin. This is responsible for uterus contractions during childbirth & for milk let down (women leaking milk from breasts)

  
  

  (2) High levels of oxytocin in females. Influenced several sex differences in behaviour e.g. responses to stress - Taylor (2000), "tend & befriend" response in dangerous situ, protect offspring by forming alliances with other women, no running = put kids in danger.
• (AO1) Role of testosterone in sex and gender

  (1) Testosterone - determines male sexual characteristics (e.g. facial hair, deeper voice, increased muscle mass) and has been linked to aggression in animal studies. (Van de Poll)

  
  

  (2) E.g. Similarly, Dabbs et al found - high testosterone levels in men convicted of domestic violence, suggesting link between testosterone and aggressive behaviour.

  
  

  (3) Testosterone may be responsible for increased size of an area of the hypothalamus in males (2.5 times greater in males) - the sexually dimorphic nucleus (SDN).
• (AO1) Role of oestrogen in sex and gender

  Oestrogen also plays a significant role

  
  

  (1) Affects female sexual characteristics (breast development, regulation of menstrual cycle) & menstruation (ensuring proper functioning of reproductive system)

  
  

  (2) Also linked to emotional behaviour e.g. (PMS) pre-menstrual syndrome

  
  

  Women with fluctuating levels of oestrogen may experience changes in mood, becoming more emotional, argumentative or even more prone to aggression during certain times of their cycle.

  
  

  Suggests oestrogen influences physical & psychological aspects of sex/gender
• (AO3) Strength - DR

  P: David Reimer provides evidence for the role of chromosomes in gender

  
  

  E: Born male, raised as girl due to circumcision accident when baby. Suffered with dysphoria during childhood. Eventually, parents told him he was boy, then lived life authentically as male. Sadly, took own life due to trauma, felt trapped in wrong body. Despite Dr Money (gender psychologist) belief that gender determined by how children raised, not case for David, who rebelled against being raised as girl.

  
  

  E: Suggests chromosomes & early exposure to testosterone explains development of gender.
• (AO3) Add however point to DR - supports trans community+ addition

  However:

  Important to note DR changed gender without knowledge/consent and crucially, without suffering gender dysphoria prior to change.

  
  

  Thus, the study should not be used to discredit people who suffer from gender dysphoria.

  
  

  It shows you cannot force a person to become a gender - arguably providing more support to the trans community.

  
  

  Addition: Factor to consider - had monozygotic twin, who also experienced severe depression, ending in life before DR.
• (AO3) Limitation - Animal studies

  P: Young's research on rats provides evidence for role of hormones in gender behaviour.

  
  

  E: Found f rats exposed to high testosterone levels in uterus (during early development) developed masculine behaviour - increased aggression, territoriality and exploration. Also, offspring played more aggressively - had increased SDN size and showed more exploratory behaviour than female offspring not exposed to testosterone.

  
  

  BUT: Extrapolation issues - findings may not fully apply to humans - given that gender is more complex in humans due social/cog influence
• (AO3) Limitation - Bio Reduct

  Point: While hormones play role in gender, their influences is complex, as both testosterone and oestrogen are presented in males and females.

  
  

  Evidence: But, focusing solely on hormones (and also genes) can lead to biological reductionism, as it oversimplifies gender development, reducing gender to just one component, ignoring social and psychological factors.

  
  

  Evaluate: A more holistic view considers how a combination of influences - such as high testosterone environment, interactions with peers, and cultural expectations also shape gender development.
• Conclusion

  This explanation focuses on sex rather than gender, as it does not account for the influence of social and environmental factors.

  
  

  SLT provides a more sufficient explanation, as children observe behaviours shown by their same-sex role models, and imitate and identify with them.

  
  

  It is naive to assume that all gendered behaviour stems solely from a biological origin, as other influence also play a crucial role.
• Quick extra facts about DR

  • Born Bruce Reimer
  • Penis accidentally removed
  • Dr Money wanted to test out the SLT of gender development
  • Raised as Brenda
  • At age 12, told truth of biological sex
  • Then became David