Chromosomes come in pairs. Normally, each cell in the human body has 23 pairs of chromosomes (46 total chromosomes). Half come from the mother; the other half come from the father.
Two of the chromosomes (the X and the Y chromosome) determine if you are born a boy or a girl (your gender). They are called sex chromosomes:
- Females have 2 X chromosomes.
- Males have 1 X and 1 Y chromosome.
The mother always contributes an X chromosome to the child. The father may contribute an X or a Y. Therefore, it is the father that determines the gender of the child.
The remaining chromosomes are called autosomal chromosomes. They are known as chromosome pairs 1 through 22.
For detailed information, see heredity and disease (genetics).