Answer:
The answer is 50
Explanation:
Hemophilia is a X-linked disease. That means the recesive allele which causes the disease is not in Y chromosome, but only in X chromosome. If we denote:
X⁺ : dominant allele
X⁻: recesive allele
Then, in a woman there are three posibilities:
X⁺X⁻: is a carrier woman (without hemophilia)
X⁺X⁺: healthy woman
X⁻X⁻: woman with hemophilia
But in a man there are two posibilities:
X⁺Y: healthy man
X⁻Y: man with hemophilia
A man with hemophilia is X⁻Y, and a healthy woman whose mother had hemophilia is a carrier woman (X⁺X⁻). If they have a child, there are 4 posibilities, and each one has 1/4 of occurrence probability:
X⁻Y x X⁺X⁻ = X⁻X⁺, X⁻X⁻, X⁺Y, YX⁻
Posibilities with hemophilia are X⁻X⁻ and YX⁻ (1/4 + 1/4= 1/2= 0.5= 50%)
In each filial, there is a 50 percent of probability of having a child (man or woman) with hemophilia.
