You have a sister who is a carrier for hemophilia, yet she has normally clotting blood. If she had children, who is most likely to be affected with this disorder?

Question

Quizplus · Accepted Answer

Hemophilia is a sex-linked recessive disorder, meaning it is carried on the X chromosome. Since your sister is a carrier, she has one X chromosome with the hemophilia gene and one X chromosome with the normally clotting gene. If she has a male child, the child will have a 50% chance of inheriting the X chromosome with the hemophilia gene, which would result in the child having hemophilia. If she has a female child, the child will have a 50% chance of inheriting the X chromosome with the hemophilia gene, but since she has a second X chromosome with the normally clotting gene, the female child will likely not have the disorder, although she will be a carrier.

You Have a Sister Who Is a Carrier for Hemophilia