Typically in mammals, the gender of an organism is determined by the sex chromosomes. In the case of humans, this happens to be the X and the Y chromosomes. So as you may recall, if you are XX, you are female. If you are XY, you are male.

Do chromosomes determine gender?

Two of the chromosomes (the X and the Y chromosome) determine your sex as male or female when you are born. They are called sex chromosomes: Females have 2 X chromosomes. Males have 1 X and 1 Y chromosome.

What determines your gender?

The factors that determine our assigned sex begin as early as fertilization. Each sperm has either an X or a Y chromosome in it. All eggs have an X chromosome. ... A person with XY chromosomes usually has male sex and reproductive organs, and is therefore usually assigned biologically male.