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: Genetic inheritance of hemophilia.
Hemophilia is an X-linked recessive disorder. The man with hemophilia has the genotype \(X^hY\), while the woman who is a carrier has the genotype \(X^HX^h\). Step 2: Genetic cross.
The possible combinations of offspring are determined using a Punnett square: \[ \begin{array}{c|c|c} & X^h & Y
\hline X^H & X^HX^h & X^HY
X^h & X^hX^h & X^hY
\end{array} \] From the cross: \(X^HY\): Normal son. \(X^hY\): Son with hemophilia. \(X^HX^h\): Carrier daughter. \(X^hX^h\): Daughter with hemophilia. Step 3: Probability of a son with hemophilia.
Half of the male offspring (\(X^hY\)) will have hemophilia. Thus, the probability is: \[ \text{Probability} = \frac{1}{2} = 50\%. \] \[ \therefore \text{The correct answer is: 50\%.} \]