Genetic And Hormonal Explanations Of Gender.

Front 1

What is gender?

Back 1

Gender refers to a person's to a person's sense of who they are e.g. their sense of maleness of femaleness.

Front 2

What is the role genes in sex?

Back 2

Out of the 23 pairs of chromosomes, one pair determines our sex which are known as the sex chromosomes:

1) Females have the XX chromosome pairs.

2) Whereas males have the XY chromosomes.

Front 3

The importance of genetic factors:

John money (1972)

Back 3

Claimed that biological sex was not the main factor in gender development. He argued that sex of rearing was much more important and recommended that intersex individuals could be successfully raised either by a boy or a girl.

Front 4

Research support for genetic factors in gender:

Reiner and Gearhart (2004)

Back 4

1) They studied 16 genetic males born with almost no penises.

2) Two were raised as males and remained males. Whereas the remaining 14 were also raised as females but by the age of 16 they identified themselves as males.

3) This research suggests that biological factors have a key role in gender development.

Front 5

How do hormones link to gender?

Back 5

Hormones determine the gender of the individual either by releasing hormones:

1) Prenatally, e.g. testosterone...

2) Or in adolescence, i.e. a surge of hormones during puberty leads to secondary sexual characteristics.

Hormones also influences the development of genitalia and/or affect development of the brain, both of which influence gender behaviour.

Front 6

How hormones affect the development of genitalia.

Back 6

1) Normally external genitalia are in accord with genetic sex. However, in some cases the male embryo is exposed to too little male hormone causing the male to appear externally female.

2) Conversely, genetic females may be exposed prenatally to relatively large doses of female hormones, which results in in ambiguous genitalia (e.g. swollen labia resembling a penis). Such individuals are usually identified as girls at birth but they get involved in male-type activities as they get older.

Front 7

Sex difference in brain development.

Back 7

Male brain are different from females brain in many ways. For example, girls generally appear to be at social skills (such as empathising) than boys, and are more talkative, less good at spatial navigation...

These differences are mainly down to the effects of testosterone levels on the developing brain.

Front 8

Geschwind and Galaburda view on gender.

Back 8

They believed that male brains are exposed prenatally to more testosterone than female brains and this leads to the development of a masculinised brain.

If the female brain is exposed to high levels of testosterone prenatally, which may masculinise the brain.

Front 9

Evidence for hormones affecting individual's gender related behavouir:

Cognital adrenal hyperplasia (Bernebaum and Hines)

Back 9

The psychological effects of testosterone can be seen in a condition called cognetital adrenal hyperpalasia (CAH).

Its a rare condition which can affect both males and females. It causes heightened levels of male hormones. Genetic females XX with the condition are often described as tomboys, have higher levels of aggression than girls, prefer male toys and show superior ability in spatial task.

Front 10

Hines.

Back 10

Studies of aggression in girls with CAH have so far yielded inconsistent results.

Hines reports that a number of studies comparing aggression levels between CAH girls, CAH males and controls using various measures of aggression. some of the studies show significant effects while other show no differences. Most CAH research involves small samples. Lab /studies with animals tend to show that testosterone does lead to increased aggression.

Front 11

Limitations on research methods in gender (AO3)

Back 11

Most of the evidence comes from case studies or small samples of abnormal individuals. Such research studies is fraught with problems:

1) The main problem is the lack of generalisability from abnormal individuals to the wider 'normal' population.

2) A further criticism of the research is that intersexes may be more vulnerable to social influences than'normal' individuals because their biological ambiguities mean they have to search harder for clues to their identity, and this is another reason why this research may lack generalisability.