After conception, each individual in the foetus will inherit 23 chromosomes from each parent (23 pairs overall). Out of these, 22 pairs of chromosomes will account for physical characteristics such as your height, hair colour, skin colour etc. Which means that 1 pair of chromosomes are responsible in your gender. In order to give birth to a male baby there must be a Y chromosome in the form of XY which is given by the sperm cell, it is in the absence of this chromosome that female babies are developed, producing an XX chromosome balance.
In the first few weeks of pre-natal development every foetus develops identically and the only difference is the single sex chromosome inherited from the father. It is at 6 weeks that the gonads begin to develop but there is still no distinguishment between male and female sex organs. Within male genes in the Y chromosome it contains “SRY” which produces a protein called “testis determining factor” which turns the developing gonads into testicles instead of ovaries. In females, with no Y chromosome the foetus will develop into a female.
After genes have played their part in the development of sex organs it influences the development of hormones, in the Wolffian system a H-Y antigen is formed and this encourages the development of testes rather than ovaries. In the Mullerian system no hormones are released as the development of females is the natural instinct after no Y chromosome is present. However in males an anti-Mullerian hormone is there to prevent further development of female sex organs. The testes then produce androgens which stimulate the development of male sex organs.
After hormones have played a part in the development of gender this affects the brain lateralisation. There has been some evidence to suggest that females show less brain lateralisation for language abilities than males do. In males, the left hemisphere is more active than the right hemisphere