John has hemophilia and his wife carries the recessive gene but does not have the condition. If they were to have children, what is the probability that any male child would also carry the recessive gene but NOT have the condition?

Question

Quizplus · Accepted Answer

Hemophilia is a sex-linked recessive disorder carried on the X chromosome. A male child inherits his X chromosome from his mother and Y chromosome from his father. Since John has hemophilia, he has an X chromosome with the hemophilia gene. His wife, being a carrier, has one normal X chromosome and one X chromosome with the hemophilia gene. A male child will inherit the Y chromosome from John and one of the X chromosomes from his mother. Therefore, he cannot be a carrier without having the condition, as males with the hemophilia gene on their single X chromosome will express the condition.

John Has Hemophilia and His Wife Carries the Recessive Gene