Biological

• Biological explanation


  sex and gender are interchangeable terms. behavioural, physiological and social differences between males and females are due to differences between chromosomal and hormonal differences between male and female.Sex and gender is innate and a result of nature
• Chromosomes


  Found in the nucleus of living cells and theycarry information in the form of genes.The 23rd pair determines biological sex
• Male chromosomes


  XY

  Makes produce more testosterone than females

  have penis/testes
• Female chromosomes


  XX

  Females produce more oestrogen than males

  have vagina/ovaries
• How chromosomes work


  The sex of a baby is determined at conception when the sperm and ovum form azygote(fertilised egg). The sperm and the egg both contribute chromosomes to the zygote. The 23rd chromosome contains DNA instructions to determine the zygote's sex.

  The ovum can only supply an X chromosome (female); the sperm can contribute either an X or a Y chromosome (male). If the sperm contributes a Y chromosome the zygote will be genetically male (XY, if the sperm contributes an X the zygote will be female (XX).

  Male and female embryos up to 8 weeks have external genitalia that look the same.At 8 weeks, genetically XY males produce androgens which stimulates the development of male genitalia. In XX females this process does not take place, thus female genitalia develop.
• Hormones


  chemical substances secreted by glands throughout the body and carried in the bloodstream. The same sex hormones occur in both men and women, but differ in amounts and in the effect that they have upon different parts of the body. Hormones affect the development of the brain which influences gender behavior (e.g. male testosterone and aggression).
• Testosterone


  Hormone which ismore present in males than females, and affects development and behavior both before and after birth. Testosterone, when released in the womb, causes the development of male sex organs (at 8 weeks) and acts upon the hypothalamus which results in the masculinisation of the brain.Testosterone can cause typically male behaviors such as: Aggression, competiveness and higher sexual drive.Appears that in males brain hemispheres work more independently than in females, and testosterone influences this lateralisation.
• Oestrogen


  Oestrogen infemales governs the development of secondary sexual characteristicsand menstruation from adolescence onwards. Oestrogen is a female hormone that determines female sexual characteristics and menstruation. Oestrogen causes some women to experience heightened emotionality and irritability during the menstrual cycle.
• Oxytocin


  A hormonereleased by the posterior pituitary that stimulates uterine contractions during childbirth and milk ejection during breastfeeding.men and women produce amounts of oxytocin during sexual activities which may aid to their bonding. (less for men)
• Diamond (AO3)


  Gave pregnant rats testosterone (androgen) injections. The female offspring's behaviours showed masculine rat behaviours such as being territorial, aggressive and mounting other female rats (sexually dominant behaviour). They changed behaviorally into male rats. This research demonstrates that testosterone is responsible for the development of male and females behaviours which supports the idea that gender development is due to biology (nature).However, animal study! the physiology of rats is different to humans
• David Reimer


  He was Born boy (Bruce) and had his penis burnt off after a circumcision accident during surgery. Although he seemed to have been successfully raised as a girl,he became depressed as a teenager and his parents informed him of the truth. He began to live as a male (David) and stated that he never felt like a female during his childhood. The outcome of the case study support that biological argument that his sex chromosomes (XY) and hormones were more powerful in determining his gender identity (nature) rather than how he was raised (nurture).However, as this was a unique case study, it is difficult to generalise the findings to other people in regards to assumptions about the biological nature of sex and gender.
• Limitation of biological explanations

  Too deterministic! they assume that Genetics and Biological are enough to provide a sufficient explanation for sex and gender.
• Klinefelter Syndrome (XXY)


  an extra X chromosome causes physical abnormalities in boys(1 in 600 male births)physical characteristics- breast enlargement- infertile- overweight- lack of facial and body hairpsychological issues- language impairmentpractical application- testosterone replacement therapy - deepen voice and stimulate hair growth
• Turner Syndrome (XO)


  A missing X chromosome (45 instead of 46) in females can cause intellectual disability and sexual underdevelopment(1 in 2000 female births)physical characteristics- short stature- webbed neck- heart defect- pre-pubescent appearancepsychological issues- low reading ability- low maths ability- low visual memory skillspractical application- growth hormones and oestrogen replacement therapy
• Nature vs nurture


  Nature vs. Nurture - Studying people with Turner's syndrome and Klinefelter's syndrome might help our understanding of gender because by studying people with atypical sex chromosomes and comparing their development with that of people with typical sex chromosomes, psychologists are able to establish which types of behavior are genetic (e.g. determined by chromosomes).However, we need to be cautious generalising from research conducted on people with Klinefelter's or Turner's as those who come forward for research may not be typical of all people with the conditions (For e.g. only 1/3 of people with Klinefelter's know they have the syndrome).Girls with turner's syndrome are socially immature and have trouble fitting in - however this may be due to nurture as they look younger and people interact with them immaturely