Hemophilia A pedigree.

This pedigree illustrates a common X-linked recessive inheritance pattern for hemophilia A. Carrier females are marked separately from affected males, making the route through generations easy to follow. An unaffected father and carrier mother can have affected sons, carrier daughters and unaffected children. The carrier daughter in the next generation then has an affected son, which makes the pattern visible without adding unnecessary detail. Clinicians and students use examples like this to discuss why family history matters and which relatives may need assessment. The chart records reported status; it does not establish a diagnosis or replace factor testing and genetic counseling.