Genetic disorders that are spread from parent to offspring are caused due to mutations in either the X or the Y chromosome. Females have two X-chromosomes which they receive from each of their parents while males have one X-chromosome and one Y-chromosome; the X-chromosome comes from the mother and the Y-chromosome from the father.
Males can be affected by diseases that are caused due to mutations in the X-chromosome.
These are of two types, recessive and dominant. X-linked recessive disorders are acquired predominantly by males as they have only one X-chromosome. As females have two X-chromosomes, the normal one compensates for the one that is defective. They are affected if they get two mutated X-chromosomes, one from each parent. In these disorders, the females are usually carriers.
In X-linked dominant disorders just one mutated X-chromosome is required to cause the disorder. Both males and females are equally affected by these.