The biological explanation for sex and gender

• Outline the role of chromosomes and hormones on sex and gender.

  If a sperm cell carries a Y chromosome, it causes the XY (male) foetus to have the SRY gene.

  The SRY gene leads to the development of testes in males.
• Outline the role of chromosomes and hormones on sex and gender.

  The testes secrete higher amounts of testosterone which leads to male sex characteristics (e.g. muscle mass and facial hair) as well as masculine gender characteristics (e.g. increased aggression).
• Outline the role of chromosomes and hormones on sex and gender.

  The absence of the SRY gene in XX (female) foetuses results in them developing ovaries.

  The ovaries secrete higher amounts of oestrogen which leads to female sex characteristics (e.g. breast development and wider hips) as well as feminine gender characteristics (e.g. increased empathy).
• Outline the role of chromosomes and hormones on sex and gender.

  Oxytocin is another hormone that can affect gender characteristics i.e. women produce larger amounts of oxytocin than men and it has been linked to their increased compassion and ability to bond with others (tend and befriend responses rather than fight or flight).
• Evaluate the role of chromosomes and hormones on sex and gender: supporting evidence. 


  Klinefelters is a disorder in men whereby they have XXY chromosomes. which results in them developing atypical sex characteristics such as increased breast growth. They are more shy and passive.

  Turner’s is a disorder in women whereby they have XO chromosomes, which results in them developing atypical sex characteristics such as less breast development. They tend to have poorer social skills. This is a strength as it shows how chromosomes can lead to changes in both sex and gender.
• Evaluate the role of chromosomes and hormones on sex and gender: confounding variables. 


  Klinefelter’s males may be more shy and passive because they are more likely to be bullied for their atypical features (e.g. breast growth). Females with Turner’s syndrome may have more difficulty fitting in because they are more likely to be bullied for their atypical features (e.g. webbed neck). This is a limitation because it suggests that environmental factors rather than chromosomes are influencing their gender development.
• Evaluate the role of chromosomes and hormones on sex and gender: supporting evidence.


  Administering testosterone in female-to-male individuals has been found to lead to male sex characteristics (e.g. facial hair) and masculine gender behaviours (e.g. increased aggression). Male-to-female individuals have received oestrogen which has been found to lead to female sex characteristics (e.g. breast development) and feminine gender behaviours (e.g. a decrease in aggression). This is a strength as it shows how hormones lead to sex and gender characteristics.
• Evaluate the role of chromosomes and hormones on sex and gender: confounding variables. 


  The change in gender characteristics seen in transgender individuals receiving hormone therapy may not be due to the hormones. Instead, they may be unconsciously or consciously trying to show the behaviours that are expected of that sex. It may be that they identify as a man and, because there is a sex-role stereotype that men should be more aggressive, they behave in a way to suit this sex-role stereotype.