# 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.

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.

##### 1 Answer

Jul 6, 2018

#### Answer:

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.

#### Explanation:

Since the normal woman's father had hemophilia, she is a carrier. She inherited her father's