Role of chromosomes and hormones in sex and gender Flashcards
What are chromosomes?
X-shaped bodies that carry all the genetic info (DNA) for an organism. Each person has 23 pairs. Determine physical and behavioural characteristics.
Explain how chromosomes influence sex.
All ova (eggs) are X, sperm can be X or Y. Forms the sex chromosome - XX for female, XY for male. Fertilisation happens by chance. Usually a direct link between individuals chromosomal sex and the external genitalia.
When does the foetus go from appearing gender neutral to appearing male/female?
3 months after conception. Testosterone causes male to develop external genitalia.
When does the foetus go from appearing gender neutral to appearing male/female?
3 months after conception. Testosterone causes male to develop external genitalia.
How can chromosomes also influence a person’s sense of gender?
Link between chromosome pattern and external genitalia which produce hormones, which influence more gendered behaviours.
What are the 2 atypical sex chromosome patterns?
Klinefelter’s syndrome - XXY
Turner’s syndrome - XO
Outline Klinefelter’s syndrome.
XXY. 1 in 1000 males. Fairly normal development, taller with less muscular coordination, less testosterone = less masculine facial features e.g. less facial hair, broader hips and sometimes breast tissue. Have genitals but often infertile.
Outline Turner’s syndrome.
XO. 1 in 2000 females. Shorter than average, absence of mensturation, narrow hips, webbed neck. Have genitals but often infertile.
What are hormones?
The body’s chemical messages that travel through the bloodstream, influencing many physiological processes.
Name 3 hormones that influence gender.
Testosterone, oxytocin, oestrogen.
Explain the role of testosterone in influencing gender.
Produced more in males. Prenatal development of genitalia (primary sexual characteristics). Post natal development of secondary sexual characteristics such as facial hair and deep voice. Mat affect brain development - females exposed to more testosterone produce more tomboyish behaviour.
Explain the role of oestrogen in influencing gender.
Produced more in females. Female is default gender, so don’t need hormones to develop primary sexual characteristics. Oestrogen important in secondary sexual characteristics development - widened hips, breast development.
Explain the role of oxytocin in influencing gender.
Produced more in females. Love hormone - inhibits fight or flight to initiate tend and befriend. Milk production. Linked to orgasm and wound healing.
(AO3) Outline intersex conditions.
AIS in men. Unresponsive to or produces very little testosterone. Lack of physical primary characteristics - no penis.
CAH in women. Over-exposure to testosterone. Outward male appearance. Often tomboyish and accidentally labelled male.
Shows importance of hormones.
(AO3) Describe research that supports the biological determinism of gender assignment.
Reiner and Gearhart studies 16 genetic males with no penis. 2 raised male, remained male. 14 raised as females. Of those, 8 reassigned themselves as males by age of 16. Shows the importance of underlying genetic factors despite being raised as the opposite gender.
(AO3) Describe a case study for the importance of biology in gender.
David Reimer invested by John Money. Money argued that biological sex was not the most important factor in gender development. David Reimer was intersex (male but botched circumcision) and Money argued individuals like him could be healthily raised as either gender. Initially claimed gender reassignment was successful - healthy has his twin brother. But when told he was biologically male, he showed strong male identity despite being raised female. Eventually committed suicide due to the events.
(AO3) Describe the issues with research into the influences on gender and gender abnormalities.
Often include the study of unique individuals or groups of people. E.g. individuals raised as the opposite gender or particularly low/high testosterone are likely to have very abnormal experiences of the world compared to an individual with regular gender development. Suggests the findings from such studies need to be generalised with caution as they may lack population validity.
