Genes carried by sex chromosomes.
There are two different sex chromosomes X and Y . Men usually have a combination of a X and a Y chromosome, whereas women usually have two X chromosomes.
The chromosomes do not only determine the gender, but also carry information about other characteristics. All the genes on the X and Y chromosomes are called sex linked genes .
Both men and women can have the X-linked genes , since both inherit X-chromosomes. However, only men can have the Y-linked genes .
The X-chromosome is quite large and contains approximately 1100 genes. The Y-chromosome is much smaller with only about 25 genes.