What is a defining feature of the behavior of X-linked dominant disorders in terms of male inheritance?

In X-linked dominant disorders, a notable characteristic is that if a male is affected, all of his daughters will inherit the affected X chromosome and thus will also be affected by the disorder. This transmission occurs because males have only one X chromosome, which they pass on to all of their daughters. In contrast, males pass their Y chromosome to their sons, so affected males do not transmit the disorder to their sons since sons inherit the Y chromosome from their father.

This defining inheritance pattern highlights why daughters of affected males will invariably display the disorder; they receive the affected X chromosome from their father. In contrast, male carriers are not possible in X-linked dominant disorders because they only possess one X chromosome, which, if affected, expresses the disorder without the possibility of being a carrier.

Understanding this aspect is crucial for genetic counseling and anticipating the pattern of inheritance in families with X-linked dominant disorders.