Question

Hemophilia is an inheritable genetic disorder that prohibits the proper formation of blood clots. The recessive gene that causes hemophilia is located on the X-chromosome. Given this information, which of the following statements is true?

Answer 1

Technically, choice 3 is correct, but it is a poor answer:

Choice 1: Both parents would have to carry the recessive gene to produce a female child with hemophilia.

Choice 2: A male with hemophilia would have girls who are carriers (one copy of the recessive gene), but they would not have hemophilia.

Choice 3: If a woman has hemophilia (two copies of the recessive gene, which is extremely rare) then all of her sons will have hemophilia and all of her daughters will be carriers.

Choice 4: If the father has hemophilia, then none of his sons will have the disorder because his sons receive only the y chromosome from their father.

Hemophilia is typically inherited from a mother who is a carrier (has one copy of the recessive gene).