Biological sex is determined by genes, which are found on our chromosomes. Humans have 23 pairs of chromosomes, with one pair determining our sex. Females are found to have an XX pair whilst males have an XY pair. Chromosomal sex largely controls how masculine or feminine an egg’s development will be.
Depending on your chromosomal pairs, an embryo will either develop testes of ovaries. The SRY Gene on the Y chromosome causes the gonads to develop into Testes, while an absence of this gene will cause the gonad’s to develop into ovaries. The development of these genitalia strongly influence gender development as they affect the production of hormones. Social and environmental factors can also have a big influence.
Hormones largely affect the development of genitalia. Androgens (male hormones) for example Testosterone stimulate the development of the testes. Genetic females who are prenatally exposed to unusually large levels of androgens may consequently develop ambiguous genitalia and the baby may externally appear to be male. This is similar to males, who if they aren’t exposed to enough androgens, may appear to externally be female. This condition is coined as androgen insensitivity syndrome.
Hormones also have a powerful effect on the development of the brain. Females and males have different brains, with females generally being more advanced in social skills such as empathising, whereas males generally excel at spatial skills. As a result, it is thought that testosterone makes the brain more masculine, by stimulating areas of the brain associated with spatial skills.
Research has demonstrated the effect on gender development. Daedy et al found that in biological females, high levels of salivary testosterone were linked with low scores on measures of maternal personality. This shows that testosterone has the effect of making the brain more masculine. This supports the biological theory towards gender as it shows a link between hormones and gender. However, this relationship may not be causal as correlation does not imply causation; for example, testosterone may affect the levels of other hormones which have an effect on the maternal personality instead.
On the other hand, there is evidence that biological sex is not…