Hemophilia a Is an X-Linked Recessive Genetic Condition

Multiple Choice

Hemophilia A is an X-linked recessive genetic condition.In humans it is due to a mutation in the F8 gene,which encodes a protein called coagulation factor VII.Coagulation factors are proteins important in blood clotting.Individuals with hemophilia,when injured,bleed longer than a normal,healthy individual;the inability to normally clot blood can be life threatening.Which of the following statements is NOT a reason why hemophilia is much more common in males than in females?

A) A female with one defective allele makes enough normal coagulation factor VII to clot blood and will not have hemophilia A
B) Males are hemizygous for the F8 gene,so they will have hemophilia A if they have one defective allele
C) Females have to receive a defective allele from both their mother and their father to get hemophilia A
D) Males have to receive a defective allele only from their father to get hemophilia A