4 Biological approach Jost (1970) found: Rats & rabbits - if we remove the ovaries in the embryotic stage, it makes little difference to development – still develops into a girlBUT if we remove the testicles (begins as a boy), the baby rat will develop differently and become a girlITS ALL ABOUT THE ‘Y’ (chromosome)
5 jost Jost proposed that: Natural form of all human babies is F Y chromosome seems to be highly correlated with ‘biological vulnerablilty’ before birth and after birth- more likely to conceive a boy
6 Jostmore boys are aborted in the early stages of pregnancy or are stillbornmore boys die of trauma during birth -Throughout life men are more susceptible to certain illnesses:E.g.Heart disease, certain types of cancer, viruses, cerebral palsy
7 discussionHow many people believe in the traditional gender roles nowadays?Do you think things have changed in terms of men as breadwinners and woman as homemakers?Who thinks men and women are more suited to different roles?Would everyone agree that women are more nurturing than men?Are little boys more rough when playing than little girls?
8 researchAnimal studies: Have provided evidence of the effects of hormones on behaviourGoy & Rosko (1968):Injected pregnant monkeys with testosteroneObserved their female offspring
9 researchFOUND:Their behaviour was more like that of M monkeys - more aggressive & M sexual behaviour. Some monkeys even developed penises instead of a clitorisRats injected with opposite sex hormones during early development also exhibited opposite-sex type behaviour
10 evaluationWhether or not this applies to humans is debatable - we cannot carry out such studies on human embryosHoWeveR some studies have been conducted on humans who have developed ‘abnormal’ hormonal conditions…
11 Testicular feminising syndrome More properly called Androgen Insensitivity Syndrome (AIS)E.G = pseudohermaphraditismOccurs when:Normal XY [male] foetus does not develop testosterone receptors in the bodyThus is insensitive to testosterone - still produced but body does not pick it upLack of influence from testosterone = foetus will not develop testes & will develop into a ‘female’Externally = looks F but internally are M [without testes
13 pubertyTesticles (undescended) begin to produce a lot of androgens BUT body still can't respond normallyHoWeveR it can convert testosterone into oestrogen [female hormone]– so person develops voluptuous breasts, very little body hair- BUT will have no uterus = no menstrual cycle & infertile
14 Goldwyn case study Daphne Went Visited her doctor for help after experiencing problems falling pregnantDiscovered she was not entirely femaleShe was married and went on to adopt two children and lived happily as a woman
15 Androgenital syndrome This is the reverse of Testicular feminizationNormal chromosomal F receives too many M hormones during embryonic developmentMight happen if mother gets hormone injections during pregnancy [sometimes given to avoid miscarriage]In extreme cases - female baby can develop M external genitalia [penis and scrotum] but internally is still F
16 Turner syndromeTurner syndrome is a genetic syndrome that only affects femalesIt is caused by an abnormal sex chromosomeFemales usually have two x chromosomes (XX)Girls with turner syndrome only have one full x chromosomeThe characteristics are often to do with growth and underdeveloped ovaries
17 What does this have to do with gender identity? Well… Money & Hines (1972) & Hines (1982) studied females exposed to male hormones before birthFOUND:girls displayed more typically masculine behaviours than those not exposedBUT interpretation of results can be criticised as children who are exposed to abnormal levels of M hormones are often born with genital abnormalities– masculine behaviour could reflect her own and others reaction to her more masculine appearance
18 evaluationBiological approach assumes we can separate nature and nurtureSome biologists dismiss nurture whiles some simply believe it plays a smaller role than biology in determining sex rolesBiological evidence is far from clear
19 evaluation Generalising from animals to humans is not clear-cut Studies of hermaphrodites & pseudohermaphrodites seems to show that assigned sex at birth determines sex role characteristics rather than biologyHayes (1994), "looking at human gender behaviour purely as a result of ‘biological sex is not very likely to provide us with a full explanation."
20 evolution What is meant by ‘natural selection’? Only the strongest, fittest species survive to reproduce – the rest…Males = physical strength, greater lung capacity = better suited to hunting & defending family/territoryFemales = childbearing, milk producing = reproduction, child-rearing, nurturing, domestic labour
21 PARENTAL INVESTMENT THEORY (Kenrick, ’94) Inexpensive for men and costly for women - Why?Men can reproduce many more times during the course of a woman’s pregnancy – leaving plenty more time for men to produce more babies in the time it takes a woman to create and grow just one!Human infants are born cognitively & physically immature - cannot survive on their own – a woman therefore is ‘bound’ to care for a child until capable of self-care, taking several years – thus leaving yet more time for men to father yet more babies
22 Other key termsPhenotype: can be described as the characteristics of an individualGenotype: can be descried as the genetic make-upNature: is genetic/ inheritedNurture: is down to environmental influences
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