the role of chromosomes and hormones

• Chromosomes

  Found in the nucleus of living cells and carrying information in the form of genes. The 23rd pair of chromosomes determines biological sex.
• Hormone

  A biochemical substance that circulates in the blood but only affects target organs. They are produced in large quantities but disappear quickly. Their effects are very powerful.
• Testosterone

  A hormone from the androgen group that is produced mainly in the male testes (and in smaller amounts in the female ovaries). Associated with aggressiveness.
• Oestrogen

  The primary female hormone, playing an important role in the menstrual cycle and reproductive system.
• Oxytocin

  A hormone which causes contraction of the uterus during labour and stimulates lactation.
• the role of chromosomes

  • made from DNA
  • 46 chromosome - 23 pairs
  • female = XX
  • males = XY
  • all normal egg cells produced by human ovary have an X chromosome
  • sperm carry an X or Y chromosome - determines baby's sex
  • Y chromosome carries a SRY gene - causes testes to develop - produces androgens (male sex hormones)
• the role of hormones

  • prenatally in womb hormones act upon brain development and development of the reproductive organs
  • puberty - burst of hormonal activity triggers the development of secondary sexual characteristics - pubic hair
• testosterone

  • male hormone
  • controls the development of male sex organs during foetal development
  • high levels of testosteronene - aggression, spatial skills - adaptive
  • allows males to compete for the opportunity to mate with a fertile female - hunter role
  • impact the hypothalamus in the brain
• oestrogen

  • female hormone
  • determines female sexual characteristics and menstruation
  • cause women to experience heightened emotionality and irritability during menstrual cycle
  • premenstrual syndrome - has been used as a defence of shoplifting and murder
• oxytocin

  • women produce larger amounts than men
  • stimulates lactation - breastfeeding
  • reduces stress hormone cortisol and facilitates bonding - love hormone
  • released in massive quantities during labour and after childbirth
  • suggests why men are less interested in intimacy and closeness
• AO3 - role of chromosomes and hormones - strength

  P: evidence supports the role of chromosomes and hormones in gender development

  E: Wang - link between increased testosterone and sexual behaviour - male hypogonadism condition caused by a man's testes failing to produce normal levels of testosterone

  • after testosterone therapy it improved sexual function, libidio and mood and significant increases in muscle strength observed in sample

  L: shows that testosterone exerts a powerful and direct influences on male sexual arousal as well as physical development well into adulthood
• AO3 - role of chromosomes and hormones - limitation

  P: ignore the role of social factors in gender-related behaviour

  E: Hofstede - claims that gender roles around the world are much more a consequence of social norms than biology where notions of masculinity and feminity with whether it is individualist or collectivist cultures

  E: countries that place individual competition and independence over needs of community - masculine outlook, masculine traits more highly valued

  L: suggests social factors may be more important in shaping gender behaviour and attitudes
• AO3 - role of chromosome and hormones - limitation

  P: reductionist

  E: reduce gender to the level of chromosomes and hormones have been accused of ignoring or underplaying alternative explanations

  E: cognitive approach - draw attention to the influence of thought processes such as schema

  psychodynamic approach - importance of childhood experiences such as interaction within family

  L: more complex than its biological influences alone
• AO3 - role of C+H - strength

  P: research support for the influence of chromosomes on gender identity

  E: David Reimer - botched circumcision left him without a penis - so David was raised in a feminine way - girls' clothes and toys

  • never adjusted to life as a girl - experiencing severe psychological and emotional problems
  • after truth he went back to living as a man

  E: influence of nature was stronger than nurture as even though he was treated as a girl for many years it did not affect identity as a man

  L: supporting the influence of chromosomes and hormones on gender identity