Question

In a family, a man with hemophilia, a genetic disorder where blood doesn't clot properly, marries a woman who is a carrier of the gene but does not express the disorder. What is the probability that their son will have hemophilia?

• A. 0\%.
• B. 25\%.
• C. 50\%.
• D. 75\%.

Hint:

Hemophilia is an X-linked recessive disorder. In such disorders, sons inherit their X chromosome from their mother and the Y chromosome from their father.

Answer 1

The Correct Option is C

Step 1: Hemophilia Inheritance.
Hemophilia is an X-linked recessive condition. Affected males have the genotype \(X^hY\), and carrier females have the genotype \(X^HX^h\).Step 2: Genetic Cross Analysis.
A Punnett square illustrates the potential offspring genotypes:\[\begin{array}{c|c|c} & X^h & Y
\hlineX^H & X^HX^h & X^HY
X^h & X^hX^h & X^hY
\end{array}\]The cross yields the following outcomes: \(X^HY\): Unaffected son.
\(X^hY\): Son with hemophilia.
\(X^HX^h\): Carrier daughter.
\(X^hX^h\): Daughter with hemophilia.Step 3: Probability of an Affected Son.
One out of two male offspring (\(X^hY\)) will inherit hemophilia. The probability is therefore:\[\text{Probability} = \frac{1}{2} = 50\%.\]\[\therefore \text{The correct answer is: 50\%.}\]