Atypical Sex Chromosome Patterns

• Klinefelter’s syndrome


  (AO1)

  • An atypical sex chromosome pattern which affects biological males

  • Caused by the presence of an extra X chromosome so individuals with this syndrome have an XXY sex chromosome structure
• Klinefelter’s syndrome physical characteristics


  (AO1)

  • Reduced body hair

  • Some breast development at puberty

  • Softening or rounding of body contours

  • Long gangly limbs

  • Underdeveloped genitals

  • Problems with co-ordination and general clumsiness

  • Susceptible to health issues more commonly found in females eg breast cancer
• Klinefelter’s syndrome psychological characteristics


  (AO1)

  • Poor developed language and reading abilities

  • Passive

  • Shy

  • Lack interest in sexual activity

  • Don’t respond well to stressful situations

  • Problems with executive functions (mental skills) eg memory and problem solving
• Turners syndrome


  (AO1)

  • An atypical sex chromosome pattern which affect biological females

  • Caused by an absence of one of the two X sex chromosomes so individuals with this syndrome have an XO sex chromosome structure
• Turners syndrome physical characteristics


  (AO1)

  • No menstrual cycle

  • Ovaries fail to develop so individuals are sterile

  • Have a broad shield chests (Do not develop breasts at puberty)

  • Low set ears

  • Webbed neck

  • High waist to hip ratio so hips aren’t much bigger than waist

  • Physically immature – retain the appearance of prepubescent girls
• Turners syndrome psychological characteristics


  (AO1)

  • Higher than average reading ability

  • Spatial, visual memory and mathematical abilities lower than normal

  • Socially immature – unable to relate to their peers and find it hard to fit in
• ✅ Research into atypical sex chromosomes contributes to the nature-nurture debate of gender development


  (AO3)

  • By comparing the psychological and behavioural differences between individuals with atypical and typical sex chromosomes, researchers can infer that any differences have a biological basis

  • e.g. Turner’s syndrome individuals have a higher verbal ability than typical females suggesting that these traits are linked to abnormal chromosomal structure

  • This supports the nature argument which suggests that gender development has an innate biological basis
• ❌ Counterpoint: role of nurture


  (AO3)

  • Some argue that the differences observed are due to environmental and social influences rather than biology alone

  • E.g. social immaturity in females with turner’s syndrome may be a result of others treating them immaturely due to their prepubescent appearance, reinforcing immature behaviours

  • Suggests that gender development is shaped by nurture and is not biologically determined

  • An interactionist approach which considers the influence of both nature and nurture on gender development would provide the most comprehensive explanation
• ✅ Real world application


  (AO3)

  • Research into atypical sex chromosomes has increased our awareness on Klinefelter’s and Turner’s syndrome

  • This has led to earlier and more accurate diagnosis of Klinefelter’s & Turner’s syndromes

  • This means individuals can be identified and treated from a very young age helping them manage their condition and live a normal and successful life

  • Increased awareness has improved the quality of life for individuals with those syndromes
• ❌ Sampling issues


  (AO1)

  • Studies into Klinefelter’s and Turner’s syndromes often involve small unrepresentative samples - only individuals with the most severe symptoms are typically studied

  • So the picture of typical symptoms may be distorted

  • Many individuals with Klinefelter’s don’t experience significant cognitive and psychological problems and many are highly successful academically, in their personal lives and careers

  • So the typical picture of Klinefelter’s and turner’s syndrome is exaggerated and doesn’t apply to all individuals with this syndrome