The genotype of a female refers to the specific set of DNA that she inherits, and in humans, the genotype that represents female sex is XX. This is in contrast to male humans, whose genotype is XY. Its important to note that while the genotype of women might seem simple on its face, there are many factors that make the phenotypic expression of the sex chromosomes a complex matter. Sexual characteristics arise in utero based on whether or not the Y chromosome is present to trigger a hormone release. While the sex chromosomes are simple, gender expression is not.