What characterizes an X-linked recessive disorder?

An X-linked recessive disorder is primarily characterized by its inheritance pattern through the X chromosome. In such disorders, the gene associated with the disorder resides on the X chromosome. Since males have only one X chromosome (XY), if they inherit a recessive allele on that chromosome, they will express the disorder. Females, having two X chromosomes (XX), may be carriers without exhibiting symptoms if they have one normal allele to compensate. This is why males are often more visibly affected by X-linked recessive disorders compared to females, who may only pass the gene to their offspring.

In this context, it’s important to note that while the disorder predominantly affects males due to their single X chromosome, it is not exclusively a male condition. Both males and females can inherit the gene, although the effects may differ because of the presence of two X chromosomes in females. The statement regarding transmission from father to son is incorrect, as fathers pass their Y chromosome to sons and contribute their X chromosome only to daughters, which is why such disorders cannot be transmitted directly from fathers to sons.