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What is the probability that their first son will have hemophilia?

Hemophilia is caused by several genetic factors; one, a recessive allele of an X-linked gene, is the subject of this problem. Assume that a man with hemophilia marries a normal woman whose father had hemophilia.

Answer 1

Each son has a 25% probability of having hemophilia, and each daughter also has a 25% probability of having hemophilia. The order of birth does not affect the probability of having hemophilia.

Since the normal woman's father had hemophilia, she is a carrier. She inherited her father's #"X"^"h"# chromosome and has the heterozygous genotype #"X"##"X"^"h"#.

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Answer 2

Elias Aboujaoude

The probability that their first son will have hemophilia is 50%, assuming the mother is a carrier and the father does not have hemophilia.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.