The role of chromosomes and hormones in sex and gender
- Created by: mbatchelor10
- Created on: 29-03-17 16:45
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- The role of chromosomes and hormones
- Role of chromosomes
- each person has 23 pairs of chromosomes
- sex chromosome XY = male, ** = female
- **: development of ovaries, uterus and vagina
- XY: androgens - development of testes - testosterone - development of penis - changes to brain occur
- testosterone is produced by the adrenal glands in both sexes - more testosterone in males causes genitalia to develop
- every foetus first develops female external genitalia until when the foetus is 3 months old, the external and internal genitalia differentiate
- sex chromosome XY = male, ** = female
- Atypical sex chromosome patterns
- Klinefelter's Syndrome
- the male has an extra X chromosome (**Y)
- affects 1/1000 males
- reduced testosterone - often infertile
- affects 1/1000 males
- lass facial hair, broader hips, lower IQ than siblings, tall stature, poor muscles tone, reduced secondary sexual characteristics, breasts, small testes
- the male has an extra X chromosome (**Y)
- Turner's Syndrome
- females are missing an X chromosome (XO)
- affects 1/2000 women
- lack of monthly periods as ovaries have not developed properly, short stature, often infertile
- females are missing an X chromosome (XO)
- Klinefelter's Syndrome
- each person has 23 pairs of chromosomes
- Role of hormones
- CAIS: Complete Androgen Insensitivity syndrome
- inherited condition where babies with male sex chromosomes develop into girls due to the body's intolerance to androgens
- Testosterone
- Berenbaum and Bailey (2003) - ** females exposed prenatally to relatively large doses of testosterone showed more tomboyish behaviour and greater interest in male-type activities
- testosterone during puberty is responsible for secondary sexual characteristics such as facial hair and deepening voice
- Oestrogen
- Shi et al (2005) suggested oestrogen may lead to smaller brain size
- responsible for secondary sexual characteristics such as breast development, and directing menstrual cycle (increasing blood supply to the uterus in preparation for pregnancy and maintaining it during pregnancy)
- Oxytocin
- promotes feelings of bonding and contentment & causes milk to flow in lactating mother
- produced in the pituitary glad
- dampens the effect of testosterone in males
- CAIS: Complete Androgen Insensitivity syndrome
- Evaluation
- Case Study: David Reimer
- Bruce & Brian - twins - both born male (XY). Bruce's penis was burnt off at 7 months old during a circumcision. His parents raised him as 'Brenda', with the help of Dr Money. They gave him girls toys etc. however, Bruce felt more like a boy and wanted to play with boys toys etc.
- supports the biological factors as Bruce still identified as a male as the hormones and chromosomes were very influential
- however, it is not strong evidence as there are other factors that can be taken into consideration - he had a twin brother which he can be a model for how boys should act
- the sample is too small so this evidence cannot be generalised to the whole population
- Bruce & Brian - twins - both born male (XY). Bruce's penis was burnt off at 7 months old during a circumcision. His parents raised him as 'Brenda', with the help of Dr Money. They gave him girls toys etc. however, Bruce felt more like a boy and wanted to play with boys toys etc.
- Young (1966)
- gave male hormones to female rats vice versa. - this caused a reversal of the usual gender-related behaviours
- Untitled
- gave male hormones to female rats vice versa. - this caused a reversal of the usual gender-related behaviours
- Case Study: David Reimer
- Role of chromosomes
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