X Chromosome

The 23rd pair of chromosomes are the sex chromosomes. There are two types of sex chromosomes, an X and a Y. The X chromosome is a sex chromosome that both males and females have. Females have two X chromosomes, while males have one X and one Y chromosome. In humans, the mother always contributes an X chromosome, while the father can contribute either an X (creating a female child) or a Y (creating a male child).