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 gives an X chromosome to the child. The father may contribute an X or a Y. The chromosome from the father determines if the baby is a girl or a boy.
The remaining chromosomes are called autosomal chromosomes. They are known as chromosome pairs 1 through 22.