XY chromosome

Karyotypes
The sum of all an individual's genetic information is called their genome, which is complex and unique to each person. The genome is made up of 24 different chromosomes, which occur in pairs. Each pair of chromosomes is labeled with a number one through 24. An individual inherits one chromosome in each pair from their mother and one from their father.
The XY Chromosome Pair
The 23rd pair of chromosomes is the sex chromosome pair. Females have a pair of X chromosomes (XX), while males have an X and a Y chromosome (XY). The genes on the X chromosome are responsible for a variety of traits, including hair, eye, and skin color. The Y chromosome is smaller than the X chromosome and carries only a few genes, including the genes responsible for male sex characteristics.
Male Development
The presence of the Y chromosome triggers the development of male characteristics during pregnancy. One of the genes on the Y chromosome, called the SRY gene, is responsible for the development of testes. Testes produce the hormone testosterone, which causes the development of male sex organs and other male characteristics.
Exceptions to the Rule
There are a few exceptions to the rule that females have XX chromosomes and males have XY chromosomes. For example, some individuals have a condition called Turner syndrome, which is caused by the absence of one X chromosome. Individuals with Turner syndrome are female, but they have only one X chromosome and are missing the Y chromosome.
The Importance of the XY Chromosome Pair
The XY chromosome pair is an important part of human development. It determines sex, which influences a variety of physical and psychological characteristics. The XY chromosome pair also plays a role in the development of certain diseases, including some types of cancer.