The role of chromosomes and hormones

• What is the role of chromosomes in Sex and Gender?

  • differences between sexes are a result of anatomical, chromosomal and hormonal differences.
  • 46 chromosomes - 23 pairs
  • Females XX, Males XY
  • Sex is determined by which sperm fertilises the egg
  • The Y chromosome carries the SRY gene "sex determining region Y" which triggers the development of testes
• What is the role of hormones in gender development?

  At puberty a burst of hormonal activity triggers the development of secondary sexual characteristics such as pubic hair.
• What are the three different hormones?

  • Testosterone
  • Oxytocin
  • Oestrogen
• What does testosterone do?

  • Controls development of male sex organs
  • Increased testosterone is linked with increased aggression
  • Researcher injected female rats with testosterone and found they became physically and sexually aggressive
• What does Oestrogen do?

  • Determines female sexual characteristics and menstruation
  • Causes heightened emotionality during menstruation cycle
• What does oxytocin do?

  • Stimulates lactation and plays a role in bonding
  • Women typically produce more than men due to giving birth
  • Released from the pituitary gland
• What is the case study for the role of chromosomes and hormones?

  • David Reimer
  • Bruce and Brian Reimer underwent circumcision at 6 months but Bruce's was botched with left him without a penis
  • A psychologist suggested that the parents raise Bruce in a stereotypical feminine way
  • By Bruce's teens, the psychologist had written of their success in proving gender neutrality
  • However, 'Brenda' had never adjusted to life as a female and was suffering through psychological and emotional problems
  • When she was told the truth Brenda immediately went back to living as a man (David)
• What is two limitations and one strength of the role of chromosomes and hormones in gender development?

  L: Reductionist

  S: Supporting Evidence

  L: Contradictory Evidence
• Why is the role of chromosomes and hormones reductionist?

  • Reduces sex down to chromosome patterns (XX and XY) and gender development due to hormone levels
  • As a result, the explanation ignores other factors that could play a role in gender such as environment
  • Therefore adopting a holistic approach would be more beneficial
• Why is supporting evidence a strength?

  • Supported by the case of David Reimer
  • Another researcher found that within a prison population, offenders with the highest levels of testosterone were more likely to have committed violent or sexually motivated crimes.
• Why is contradictory evidence a limitation?

  • A double-blind study conducted by Tricker
  • 43 males were given a weekly injection of either testosterone or a placebo
  • Found no significant differences in aggression after the 10 week period of the study
  • Also found that sex hormones had no constant effect on gender related behaviour

  This contradicts the explanations idea of hormones and chromosomes being responsible for increased aggression