Two mothers each give birth to a son at a busy local hospital at the same time. The son of Couple 1 has hemophilia, a recessive X-linked trait, but neither parent has the disease. Couple 2 has a son withost hemophilia, even though the father has hemophilia. The sons must have been switched at birth.

a. True

b. False

False

Explanation:

Hemophilia is a recessive trait and is sex-linked. An affected father passes the disease to the daughters. An affected or carrier mother passes the disease to her sons. A normal couple, with carrier female, can have hemophiliac son.

Couple 1 does not have the disease but the carrier mother (with no visible symptom) could have passed the allele for hemophilia to the son making him affected with the disease.

In the case of couple 2, the father has hemophilia. Being an X linked recessive trait, hemophilia is not transmitted from father to son. Only a carrier or affected mother can pass the disease to sons.

Hence, there is no genetic basis of switching of the child.