Imagine that a deaf male has a child with a hearing female. you know that the male must have the genotype dd, but the female could be either dd or dd. if the couple's first child has hearing, can you determine the mother's genotype? (hint: draw punnett squares for the two possible crosses.)

Her mother's genotype cannot be determined because it only says that the couple's first child has hearing. We cannot determine the genotype of the mother just only using the siblings or the genotye of the male or husband of the mother. So the answer in this queston is the mother's genotype cannot be determined.