Regarding the genes located on the X chromosome, women (XX) can be homozygous or heterozygous, while men (they only have one X chromosome) are always hemizygous (XY).
Two of the most characteristic examples are color blindness and hemophilia, where a recessive gene located on the differential segment of the X chromosome causes the disease. For a woman to manifest the disease, she has to be homozygous recessive, but for a man to have it, he only has to have the gene on his only X chromosome.
The color blindness or color blindness is a hereditary visual defect that causes the affected person has trouble telling red from green.
Let's look at the case of hemophilia:
Hemophilia is determined by a recessive h- allele versus the normal h+.
A carrier woman, if she has children with a normal man, can have hemophiliac or normal sons and normal and carrier daughters: