Gender: chromosomes and hormones Flashcards
how many chromosomes do we have
46
which pair of chromosomes determines sex
23rd
state female and male chromosomes
female: XX
male: XY
how chromosomes determine sex
All normal egg cells produced by a human ovary have an X chromosome
* Half the sperm carries an X chromosome and half a Y chromosome
* sex is determined by the sperm that fertilises the egg cell
* The baby will be a girl if the fertilising sperm carries an X chromosome and a boy if it carries a Y
chromosome.
what gene does the Y chromosome carry
‘sex determining region Y’ (SRY)
function of the SRY gene
The SRY gene causes testes to develop in an XY embryo. These produce androgens (male sex hormones).
* Androgens causes the embryo to become a male, without them the embryo develops into a female
define hormones
chemical substances secreted by glands throughout the body and carried in the bloodstream
when are hormones produced
in the womb, they affect brain development and production or reproductive organs
in adolescence, a surge of hormones during puberty leads to secondary sexual characteristics
eg: pubic hair
same sex hormones are present in men and women, but there are different amounts and different effects
effects of testosterone
controls development of male sex organs during foetal development
causes secondary sexual charcateristics
eg: pubic hair growth, deep voice
If a genetic female produces high levels of testosterone during foetal development, what would be the
outcome?
male sex organs will form
If a genetic male produces no testosterone during foetal development, what would be the outcome?
no male sex organ will appear
evolutionary explanation of high testosterone
high levels of testosterone is also linked to aggression because it is adaptive
Aggression towards rivals allows males to complete for the opportunity to mate with a fertile female
AO2: Nanne Van De Poll et al study
Nanne Van De Poll et al showed that female rats who had been injected with testosterone became more physically and
sexually aggressive
effects of oestrogen
determines female sexual characteristics and menstruation
explain oestrogen and PMT
Oestrogen causes some women to experience heightened emotionality and irritability during their menstrual cycle. This is referred to as premenstrual tension (PMT) > people have questioned this being a diagnosable disorder and argue its an ‘over-medicalisation’ of women
effects of oxytocin
RELEASED IN MASSIVE QUANTITIES AFTER BIRTH TO MAKE NEW MOTHERS FEEL ‘IN LOVE’ WITH BABIES
stimulates lactation, making it possible for mothers to breastfeed their children.
It also reduces the stress hormone, cortisol and facilitates bonding
how does the fact that men produce less oxytocin create sex role stereotypes.
suggests that men lack interest in intimacy and closeness within a relationship
AO3: research to support
evidence that chromosomes and hormones determine gender
eg:: David had his penis burnt of in an accident as a baby, his parents decided to raise him as a girl following their doctors
advice. As David grew older he became seemingly depressed, when his parents finally told him of his true gender he immediately “changed” back to a male, although initially he was relieved to find out the trauma of his childhood lead David
to take his own life.
supports influence of chromosomes as he was nurtured as a girl but his biological status was more important
COUNTER: unique case study so cant be generalised
AO3: research against
Mead researched a remote tribe unaffected by western norms, they had the opposite gender roles to that of
westernised societies, for instance, the males were perceived to be more decorative and domestic whereas the females were the “hunter gatherers”, they would make the important decisions in the village
gender roles are inconsistent across cultures which suggests gender doesn’t have a biological basis
AO3: evidence for testosterone
Male hypogonadism is a condition caused by a man’s testes failing to produce normal levels of the male sex hormone, testosterone.
Wang et al gave 227 hypogonadal men testosterone hormone therapy for 180 days. Significant changes in body shape, muscle strength, sexual function and libido were observed
shows that testosterone exerts a powerful and direct influence on male sexual arousal as well as physical development
AO3: reductionist
reduces gender to hormones and chromosomes which is biological reductionism
ignores other factors
eg: psychodynamic approach suggests gender is due to identification with a same-sex parent
weakness as it ignores all other factors
