The document discusses biological influences on gender development from conception through adulthood. It explains that the presence or absence of the SRY gene during early fetal development determines whether sex organs develop along male or female lines. During critical prenatal and early childhood periods, males are exposed to higher levels of testosterone than females, which influences brain development and later gendered behaviors. While hormones and genes influence gender development, the complexity of factors involved is demonstrated by cases like Caster Semenya that challenge simple biological definitions of gender.

1. Gender development
Biological approach

2. 2
Specification
Biological influences
on gender
The role of hormones
and genes in gender
development
Evolutionary
explanations
of gender roles

3. 3
The relationship between sex and gender
• The biological approach suggests there is no
distinction between sex & gender.
- biological sex creates gendered behaviour

4. The role of hormones and genes
in gender

5. 5
Biological differences between males &
females
• What makes a baby a girl or a boy?
• It can be seen as a journey in 3 steps:
Step 1 – genes
Step 2 – hormones
Step 3 – brain differences

6. 6
Biological differences between males &
females (con)
• Complexity of this issue is demonstrated by
the recent public gender testing of the athlete
Caster Semenya

7. A boy or a girl?

8. In the first 6-8 weeks
All foetuses have the same undeveloped sex organs. The
original system can develop into both male or female sex
organs. It is the presence or absence of a single gene (SRY
gene) which will dictate the future development of the foetus
as a male or a female.
(Male)
(Female)

9. Male developmentMale development
XY

10. Male developmentMale development
SRY gene produces a protein :
Testis Determining Factor (TDF)
TDF influences the development
of the gonads, they become testis
The testis produce testosterone
Testosterone triggers the
development of external male
organs i.e. penis

11. Female developmentFemale development
The absence of male hormone will result in the
development of the Mullerian system into
female sex organs

13. Between 8-24 weeksBetween 8-24 weeks: Male
foetuses are exposed to
higher levels of testosterone
than female foetuses.
From 24 weeks until birthFrom 24 weeks until birth:
gonadal hormones are low in
both sexes
The first 6 months of lifeThe first 6 months of life:
testosterone is higher in boys
than girls

14. Action of testosterone on the brainAction of testosterone on the brain

16. Men and women produce the sameMen and women produce the same
hormones but in different quantity.hormones but in different quantity.
Oestrogen
Progesterone
Testosterone
Oestrogen
Progesterone
Testosterone

17. On average, men produce
between 4 and 10mg of the
hormone per day and overall
they have about 20 times more
testosterone than women.

19. It is difficult to measure the amount
of hormones because they are very
similar and the body sometimes
converts the one into the other
Testosteron
e Progesterone
And… the body can convert one
hormone into another

20. Puberty
After around 10 years, the hypothalamus releases a
hormone which affects the anterior pituitary gland and
this causes the gonads to become active. They control
the development of secondary sexual characteristics.

21. How does testosterone influenceHow does testosterone influence
behaviour?behaviour?
Testosterone Aggressive behaviour
High sex drive
Poor language development
What evidence is there to support these statements?

22. How do oestrogen andHow do oestrogen and
progesterone affect behaviour?progesterone affect behaviour?
Premenstrual syndrome
Myth or reality?
45 % of Attempted Suicides occurred
during the week preceding Menstruation
(Wallach and Rubin, 1968)
67% of Alcohol Drinking
Binges during PMS
North Carolina Prison Study 41 % of the inmate
assaults during PMS (Ellis& Austin, 1971)
PMS has been used as a
legal defence with
varying degree of
success

23. 23
From biological differences to gendered
behaviour
• There are three sources of evidence to
assess possible links between biological &
behavioural differences:
1. Animal research
2. Case studies of atypical individuals
3. Correlational studies of the normal
population

24. Androgen insensitivity syndrome
(Testicular feminization)
Androgen insensitivity syndrome (AIS) is when a person
who is genetically male (has one X and one Y
chromosome) is resistant to male hormones called
androgens. As a result, the person has some or all of
the physical characteristics of a woman, despite having
the genetic makeup of a man.

25. 25
Support for Biological approach
-evaluation
• Evidence from biological studies has found some
support that behavioural differences may have their
origins in biology:
- Deady’s study found that women with high
testosterone levels tend to have lower scores on a
desire to have children rating scale
- Rommsayer’s study implies that lower levels of male
sex hormones may correlate with androgyny
- It explains the case of David Reimer

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