Here are a few facts about the X chromosome.
In several animal species (including mammals) the X chromosome is one of the two sex-determining chromosomes. In females, the chromosome pair is XX and males, it is XY.
Since both parents will have an X chromosome, both parents will be able to pass on an X chromosome to their offspring (only males can pass on the Y chromosome).
Several abnormalities can occur when there is an extra X chromosome or a mutation on one of the X chromosomes, including Klinefelter syndrome, Triple X syndrome, and Turner syndrome.
