the role of chromosomes and hormones Flashcards
what are chromosomes
they are made from DNA
what are genes?
they are short sections of DNA that contain instructions about physical and behavioural characteristics
how many chromosomes do we have?
46
23 pairs
which pair of chromosomes determines your sex?
the 23rd pair
what is the chromosome pair for females?
XX
what is the chromosome pair for males?
XY
what kind of chromosome do normal eggs produced by the human ovary have?
X chromosomes
what kind of chromosomes do the sperm have?
Half the sperm have an x, half have a Y chromosome
how is sex determined?
its determined by whichever sperm fertilises the egg
how is the male genitalia developed?
The Y chromosome carries a gene called “sex-determining region Y” (SRY). This gene causes testes to develop on an XY embryo. These produce androgens (male sex hormones). This causes external male genitalia to develop.
how do hormones influence gender development?
Most gender development comes about from the influence of hormones. In the womb, they act on brain development and cause the development of the reproductive organs. At puberty, they trigger the development of secondary sexual characteristics e.g. pubic hair. Males and females produce many of the same hormones, but in different concentrations.
what is testosterone, what is it controlled by and how is it transported?
A male hormone (androgen) produced largely in the testicles. The production of this is controlled in the pituitary gland and is then transported to relevant parts of the body and brain via the blood.
what is testosterone responsible for?
It is primarily responsible for the development of the reproductive organs of men. Also is responsible for a role in: sperm production, sex drive, bone mass, fat production, muscle size and strength, increased levels of aggression. All of this is likely to impact gender development/identity.
what is oestrogen?
a female hormone produced by the ovaries
what is the role of oestrogen?
It plays an essential role in the growth and development of female secondary sexual characteristics such as breasts, pubic and armpit hair, regulation of the menstrual cycle and the reproductive system.
what effects does oestrogen have on women during the menstrual cycle?
It causes women to experience heightened emotionality and irritability during their menstrual cycle. Its effect on mood, when extreme, is called pre-menstrual tension/syndrome (PMT/PMS). All of this is likely to impact on gender development/identity.
where is oxytocin produced which gender produces higher amounts of it?
It is typically produced in larger amounts in women than men. It is produced in the hypothalamus and is secreted into the blood stream by the posterior pituitary gland.
what does oxytocin do
There is lots produced after giving birth and it stimulated lactation (breast milk production). It is thought to reduce the stress hormone cortisol.
how does oxytocin make you feel?
Thought to facilitate bonding, and make individuals feel safe and secure.
how much oxytocin do both genders produce during sexual intercourse?
Both sexes are thought to produce it in equal amounts during kissing and sexual intercourse. All of this is likely to impact gender development/ identity.
AO3: how is ‘supporting case study’ a strength to the role of chromosomes and hormones in gender development?
One strength to the role of chromosomes and hormones in sex and gender is that there is a supporting case study. For example, Money wanted to develop his theory of gender neutrality so he decided to use Bruce Reimer, a 6 month old whose circumcumcision was botched leaving him without a penis. He was brought up in a stereotypically feminine way with being given dolls to play with and to wear girls clothes. By the time Bruce, known by Brenda, was in her teens, Money concluded his theory a success by this point with this being the dramatic proof of his theory of neutrality. However, once Brenda found out the truth from his parents, he immediately went back to living as a man ‘David’. Therefore, this suggests that chromosomes do in fact have a more powerful influence than the environment in gender development. HOWEVER, Brenda never adjusted to female life and was left with emotional and psychological problems and after transitioning back to David, he commited suicide in 2004, suggesting environmental influences sometimes do more harm than good to gender development.
AO3: how is ‘supporting evidence’ a strength to the role of chromosomes and hormones in gender development?
One strength to the role of chromosomes and hormones in sex and gender is that there is supporting evidence. For example, Van Goozen et al. (1995) looked into transgender individuals undergoing hormone treatments where they receive opposite sex hormones. They found that when a male transitioned to a female, there way a decrease in aggression and visuo-spatial skills whereas, when a female transitioned to a male, there was an increase in aggression and visuo-spatial skills. Therefore, this suggests that sex hormones do exert some influence on gender-related behaviours.
AO3: how is ‘contradictory evidence’ a limitation to the role of chromosomes and hormones in gender development?
One limitation to the role of chromosomes and hormones in sex and gender is that there is contradictory evidence. For example, Tricker et al. (1996) carried out a double blind study over 10 weeks of 43 males. The participants were given weekly injections of either testosterone or a placebo. They found that there was no significant differences found in aggression levels between the placebo group and the testosterone group. Therefore, this challenges the idea that the differences in behaviours shown by each gender are the results of hormones.
AO3: how is ‘reductionism vs holism’ a limitation to the role of chromosomes and hormones in gender development?
One limitation to the role of chromosomes and hormones in sex and gender is that it is reductionist. This means that a reduction of gender to levels of chromosomes and hormones ignores the role of other factors that influence gender development. For example, the cognitive approach would encourage us to consider the thought processes that are related to gender development and how we think and feel about our gender. Therefore, this can lead to us having a very restricted understanding of gender, with no recognition of the complexity of the issue.
