Question

hemophilia is a sex - linked genetic trait that affects the bodys ability to clot blood. if a normal male and a carrier female have a male child, what is the chance that the male child will have hemophilia? 0% 25% 100% 50%

Explanation:

Step1: Define genotypes of parents

Normal male: $X^H Y$; Carrier female: $X^H X^h$

Step2: List possible gametes

Male gametes: $X^H$, $Y$; Female gametes: $X^H$, $X^h$

Step3: Cross gametes for male offspring

Male children inherit $Y$ from father, and either $X^H$ or $X^h$ from mother. Genotypes: $X^H Y$ (normal), $X^h Y$ (hemophiliac)

Step4: Calculate probability

Probability = $\frac{\text{Number of affected male genotypes}}{\text{Total male genotypes}} = \frac{1}{2} = 50\%$

Answer:

50%