What is observed if the trait is localized exclusively on the X chromosome?

If the trait is localized on the X chromosome, sex-linked inheritance will be observed. This means that if the mother / father has any designated gene located on the sex chromosomes, then it is necessarily inherited in the offspring. We know that women have a set of sex chromosomes XX, and men have XY. For example, hemophilia does not occur in women, but they can be carriers, which can lead to the birth of sick boys and girls who are carriers with a 50% probability. Usually, if two hemophilia genes combine during crossing, the fetus dies.
This type of inheritance is typical for reptiles and mammals, including humans.