Question

A man whose father was a hemophiliac, but whose own blood clotting time is normal, marries a normal woman with no record of hemophilia in her ancestry. what is the chance of hemophilia in their children

Answer 1

Answer:

The correct answer would be zero percent.

Hemophilia is an X linked recessive disorder, thus, in females, two copies of the mutated gene are required to cause the disease while in males only one copy of the mutated gene is enough to produce the phenotype as males contain only one X chromosome.

As the man is normal or non-hemophiliac, his genotype would be $X^{C}Y$.

Similarly, the female is also normal with no ancestry of hemophilia. Thus, the genotype of this female would be $X^{C}X^{C}$.

The cross would result in the production of children, all having normal genotype.

Thus, the chances of hemophilia in their children are zero.