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A female is a carrier for hemophilia, and the male doesn't have hemophilia. What is the likelihood of them having a girl with hemophilia? A boy?

a) Girl with hemophilia: 0%; Boy: 100%
b) Girl with hemophilia: 25%; Boy: 75%
c) Girl with hemophilia: 50%; Boy: 50%
d) Girl with hemophilia: 75%; Boy: 25%

User Cptdanko
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1 Answer

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Final answer:

The likelihood of having a girl with hemophilia is 0% and the likelihood of having a boy with hemophilia is 50%.

Step-by-step explanation:

The likelihood of a couple having a girl with hemophilia is 0%, while the likelihood of having a boy with hemophilia is 50%.

In this scenario, the female is a carrier for hemophilia, which means she has one normal X chromosome and one X chromosome with the hemophilia gene. The male, on the other hand, does not have hemophilia and has one normal X chromosome and one Y chromosome.

Since hemophilia is a recessive X-linked disorder, a girl would need to inherit two affected X chromosomes, one from each parent, to have hemophilia. However, in this case, the female only has one affected X chromosome, so the likelihood of having a girl with hemophilia is 0%. On the other hand, a boy only needs to inherit one affected X chromosome from his mother, which is the case here, so the likelihood of having a boy with hemophilia is 50%.

User Jamie Dunstan
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