Discuss the role of genes and hormones in gender development.

(8+16 marks)


AO1 Genetics

The role of genetics in the role of gender development can be seen during the first six weeks, there are no structural differences between the embryos of those who are genetically female (XX) and those who are genetically male (XY). Six weeks after conception when sexual differentiation should occur, the genes determine whether their gonadal ridges become testes or ovaries. Fetal hormones specific to the sex chromosomes of an individual are produced at this time, where the Y chromosome of males initiates the synthesis of H-Y antigen, a protein that leads the gonadal ridges to grow into testes. If such antigen is injected into a female fetus at six weeks then a genetic female with male testes will result. Alternatively if drugs preventing H-Y from functioning are injected into a genetic male, they will be born with ovaries.

AO2

A case study that is hugely supportive of the role of genes is the David Reimer case who was studied by Money et al. Reimer was a twin but his penis was burnt off during circumcision and so Money suggested that he should be brought up as a girl and his brother as a boy to see if nurture did have an effect on Reimer’s development despite being genetically XY. During puberty he was given hormone tablets to suppress the testosterone however later on he was told of his real gender and decided to live as a boy. During the puberty stage he was particularly depressed and this is probably down to his genetics XY taking a more dominant effect over his gender development. Therefore, this additionally supports the role of nature. Further supporting evidence of Reimer’s case was completed by Reiner and Gearhart who assessed 16 XY males with no penis. Two of them were raised as boys and the other 14 as girls and it was found that 8 of the 14 switched to their real genetic gender of XY. This and Reimer’s case consequently shows that nature has more of a powerful effect over gender development than nurture and so supports the role of genetics and hormones.

AO1 Hormones

Hormones can affect the development of genitalia because during the pre-natal stage, the mother may be given testosterone hormones which, if the baby is a girl, may cause swollen labia, which can be mistaken to be a penis, and so the baby may be labeled as a boy when it is genetically a girl. This is also known as Congenital Adrenal Hyperplasia (CAH). As a result, males would experience early puberty and the girls may experience more masculine behaviours and ambiguous genitalia. Therefore this may cause complications at birth for females because the ambiguous genitalia may result in them being labeled as a boy. This shows that hormones has a significant role in gender development because it shows that if a female has too much of testosterone she can be labeled as the incorrect gender.

AO2 

There is other evidence that supports the role of testosterone affecting gender development was completed by Geschwind and Galaburda who found that prenatally, if a baby is exposed to an increased amount of testosterone in the brain, they would tend to be more masculine. Therefore this suggests why some girls are perceived to be more ‘tomboy like’ than other girls who may not be exposed to the increased testosterone. Further supporting evidence comes from Young et al who found that if a female rat is next to a male rat in the womb, they are more masculine than the other girl rats. This could be because of them being exposed to more testosterone in the brain. However, it is inappropriate to generalise these findings to that of humans because the study involved rats and so this means that the validity of the findings may not be accurate for human development. Despite this the two studies do show that hormones can play a role in gender development because the increased amount of testosterone resulted in more masculine behaviour in comparison to the other females that did not experience this.

A02

There is research to support the role of hormones from a case study of the Batista family by Imperato-McGinley et al. 10 children were although genetically XY, had Androgen Insensitivity Syndrome (AIS) whereby they did not perceive to have a penis because they were insensitive to the development of testosterone. Therefore they were labeled as a girl but during puberty they developed a penis because of the increase in testosterone. Therefore, the boys changed from being labeled as girls to boys and so thus demonstrating that hormones do have a significant role in gender development. Interestingly, the boys accepted this change but this may be a result of expectation and societal regard of males therefore it would be more beneficial to be male. This further supports the role of hormones and nature because it was not learnt and the males were born with this condition that may have possibly have been passed down in a gene, which suggests that genes too have an impact.

AO2

Although biological factors are important to gender development, other factors are also key as Dessens et al’s research challenges biological determinism. Dessens et al. studied 250 genetic females who were prenatally exposed to high levels of androgens but still raised female. 95% were content with their female gender, with only 5% experiencing significant gender dysphoria. This shows that other factors are important to gender development. 

AO2/IDA

However, these studies are case studies so therefore there is a lack of external validity, as the findings cannot be generalised to the whole population because they are rare and unique cases.

An interesting slant on the issue of biological determinism is shown in a dilemma faced by the international Olympics Committee. Since 1968 it has tested the genetic sex of all athletes
and excluded all but XX females and XY males, which meant that AIS individuals couldn't compete. In 1991 there was a ruling that genetic
sex would no longer determine entry to the games; individuals are now excluded from women's events only if they are obviously physically male (Brown, 1992). In other words genetic sex no longer determines gender.

IDA

A criticism of research and theories into gender development is that it should take ethics into consideration, as researching questions about biologically based sex differences is politically sensitive. The tendency to emphasize differences in the expected direction, arguably reinforces gender stereotypes and is potentially limiting for both males and females e.g. in choice of careers. This limits mat be self imposed or imposed by others because ‘science’ tells us they are so.