Atypical Gender Development (Biological) Flashcards
What is gender dysphoria?
- A psychiatric condition in the DSM-V.
- Individuals experience a sense of confusion about their gender, they have a strong, persistent feeling of identification with the opposite gender and stress and discomfort with their own
- It’s only diagnosed where there’s no physical intersex condition
Outline the biological explanation for dysphoria
The perception that gender dysphoria is physiologically determined
Describe the ‘transsexual’ gene
- It’s a longer version of the androgen receptor gene. The effect is the reduced action of testosterone, which affects gender development prenatally by under-masculinising the brain
- Hare et al found MtF transgender individuals were more likely to have this gene
Describe the brain sex theory
- It’s based on how male and female brains are different so perhaps transgenders’ brains don’t match their sex. The BSTc (bed nucleus of the stria terminalis) in the thalamus, which is thought to be dimorphic, (different in male and female) has been studied.
- On average the BSTc is twice as large in biological men than biological women and contains twice the number of neurons
Describe a study that supports brain sex theory
Zhou et al and Kruijver et al found that the number of neurons in the BSTc of MtF transgender individuals was similar to biological women
Outline the genetic explanation for dysphoria
Evidence suggests that gender dysphoria may have a genetic basis, twin studies assess the heritability of the condition
Describe a study that supports the genetic explanation
- Heylens et al compared 23 MZ twins and 21 DZ twins where one of each pair was diagnosed with gender dysphoria
- They found 9 of the MZ twins was concordant for gender dysphoria compared to none of the DZ twins
Give evaluation for the biological explanation for gender dysphoria (twin studies)
- Twins studies are inconclusive
- Concordance rates are low (39% for MZ twins in Heylens et al study) and it’s difficult to separate nature and nurture as twins may influence each other and share an environment
- Therefore, as gender dysphoria is rare and there’s a small sample, there’s limited generalisability for the genetic explanation
Give evaluation for the biological explanation for gender dysphoria (contradictory evidence for brain sex theory)
- Zhou argues the BSTc is fully formed at a young age
- However, Hulshoff et al studied changes in transgender individuals’ brains using MRI scans during hormone treatment and found significant changes to the BSTc over that period, suggesting it can still change in adulthood
- Therefore in Zhou et al study hormone therapy was a confounding variable as changes to the BSTc may have been caused by the therapy instead of the cause of gender dysphoria
Give evaluation for the biological explanation for gender dysphoria (other brain differences associated with gender dysphoria)
- Rametti et al studied white matter in the brain which is sexually dimorphic.
- They analysed the brains of male and female transgender individuals, before hormone treatment. In most cases, the amount and distribution of white matter corresponded more to the gender they identified with rather than their sex
- This supports the notion that there are brain differences that cause gender dysphoria
Give evaluation for the biological explanation for gender dysphoria (research refutes the biological explanation)
- Chung suggests that BTSc volume doesn’t develop fully until adulthood which contradicts Zhou’s argument
- However most transgender individuals report gender dysphoric feelings at early childhood
- This suggests that the BSTc isn’t an important structure, as it isn’t fully developed at childhood, and may not be linked to causing gender dysphoria