Gender

• What gene does the Y chromosome carry?

  SRY gene
• What does the SRY gene trigger?

  The growth of testes via the protein TDF
• What does TDF stand for?

  Testis-determining factor
• What hormones do the testes produce?

  Testosterone and AMH
• What does AMH stand for?

  Anti-mullerian hormone
• What does AMH trigger?

  The regression of Mullerian ducts and the development of wolffian ducts into male reproductive structures
• What does the Mullerian duct become?

  The female oviduct
• What does the Wolffian duct become?

  The male sperm ducts
• What three aspects of sex and gender do hormones determine?

  1. External genitalia
  2. Brain structure
  3. Potentially behavioural differences
• Oxytocin

  A hormone which also acts as a neurotransmitter that plays a role in social bonding, maternal behaviour, and sexual reproduction
• Oestrogen in Males

  Produced in small amounts in testes and adrenal glands

  Production begins during foetal development and increases during puberty but less than in women

  Levels in males are relatively stable and do not fluctuate in a cyclical pattern like in females

  Plays role in male sexual function eg libido and maintenance of bone density
• Testosterone in Females

  Produced in small amounts in the ovaries and adrenal glands

  Production begins during foetal development and increases during puberty, but the levels are much lower than in males

  Levels fluctuate throughout the menstrual cycle, with a small peak around ovulation

  Plays role in female sexual function eg libido and development of secondary sexual characteristics such as pubic hair
• Oxytocin in Males

  Produced in the hypothalamus and released from the posterior pituitary gland

  Plays a role in male physiology and behaviour

  Levels can increase in response to social interactions eg hugging or touching, and play role in social bonding and trust.

  Implicated in sexual arousal and orgasm, and promoting trust and cooperation in social interactions.
• Oestrogen in Females

  Mainly produced by the ovarian follicles

  Production begins during foetal development and increases significantly during puberty

  Levels fluctuate throughout the menstrual cycle, with higher levels before ovulation and lower levels after ovulation

  Plays role in development of female secondary sexual characteristics,

  including breast development, widening of hips, and distribution of body fat.
• Testosterone in Males

  Primarily produced in testes

  Production begins during foetal development and increases during puberty

  Levels peak in early adulthood and gradually decline with age

  Plays role in the development of male secondary sexual characteristics eg facial hair, deepening of voice, and increased muscle mass.
• Oxytocin in Females

  Primarily produced in hypothalamus and released from the posterior pituitary gland

  Levels increase during pregnancy and childbirth, promoting uterine contractions during labour and milk ejection during breastfeeding

  Involved in maternal behaviour, promoting maternal bonding and caregiving behaviours

  Levels can also increase in response to social interactions eg hugging or touching, and play a role in social bonding and trust.
• What hormone is said to sensitise neural pathways in males?

  Testosterone
• When do the two bursts of testosterone occur in males?

  As babies and at puberty, allowing brains to become primed for typically male behaviour
• Does male connectivity in the brain differ from female connectivity?

  Yes
• Are the differences in male and female brain connectivity straightforward or absolute?

  No, they are subtle with no rule
• What was the age range of children studied by Heins & Kaufman (1994)?

  3 to 8 years old
• What did Deady et al (2006) study in young women?

  Relationship between gender role and testosterone
• What link did Deady et al suggest regarding testosterone levels?

  Lower maternal drives and higher male hormones
• What were the findings of Mead (1935) regarding gender roles in Papua New Guinea tribes?

  • Arapesh: peaceful temperament, no war
  • Mundugumor: warlike temperament for both genders
  • Tchambuli: men primped, women were practical
• What was the temperament of the Arapesh tribe according to Mead?

  Peaceful in temperament
• What was the temperament of the Mundugumor tribe according to Mead?

  Warlike in temperament
• How did the Tchambuli tribe's gender roles differ from early 20th century America?

  Men primped, women were practical
• What does Mead's study suggest about gender roles?

  They can vary significantly across cultures
• Biological Approach to Gender Researchers

  Young

  Koopman

  Berenbaum and Heins

  Heins and Kaufman

  Deady et al

  Mead
• Young Research (1966)


  Male rats typically mount from behind during sex, whilst females adopt the Lordodis position

  Female rats were given male hormones during critical period of development, which reversed their future sexual behaviour

  The male hormones were thought to have enlarged the sexually dimorphic nucleus within female rats

  This shows the link between hormones and behaviour between sexes
• What position do female rats typically adopt during sex?

  The Lodordis position
• What were male hormones thought to enlarge in rats?

  The sexually dimorphic nucleus
• What animals did Young observe?

  Rats
• Koopman 1991 Research


  Implanted SRY gene (Y) in female mouse embryos

  They developed into male mice

  This shows how the presence of the SRY gene determines reproductive organs
• What animals did Koopman study in 1991?

  Mice
• Koopman 2008 Research


  Found that XX males occur approximately once in every 20,000 births

  This suggests reproductive development is more complex than simply the presence of the SRY gene
• Did Koopman's two pieces of research agree or disagree?

  Disagree
• Berenbaum and Heins (1992)


  Found females with CAH spent an increased amount of time playing with boy’s toys and less time playing with girl’s toys in comparison to a control group

  Males with CAH showed no difference to their control counterparts.
• Heins and Kaufman (1994)


  Looked at play preference amongst children between 3 and 8

  There was a male and female group with CAH and a male and female group without CAH

  Found males with and without CAH had little difference in who they chose to play with, while females with and without CAH displayed a significant difference in who they chose to play with: 44.1% CAH chose male playmates vs 11.2% controls

  This suggests the hormones exposed to as a foetus influence play preference later
• Did males with or without CAH show a difference in play preferences?

  No