In humans, a type of blindness is due to a dominant allele; normal vision is the result of a recessive allele. migraine headaches are due to a dominant allele, and normal (no headaches) is recessive. a male who is heterozygous for blindness and does not suffer from headaches marries a woman who has normal vision and does not suffer from migraines. could they produce a child with normal vision who does not suffer from headaches? if yes, can the probability of such a child be determined?

Yes.

Probability of such child = 1/2 or 50%

Explanation:

According to the question, below are the genotypes and phenotypes possibilities:

aa = normal vision & no headache

Aa = normal vision & no headache

AA = blindness & headache

                                                                      Male                       Female

                                                                        Aa                            aa

Possible genotypes of progeny:            Aa        Aa           aa         aa

So it is clear that out of the 4 probable children, 2 with 'genotype aa' will have normal vision & no headache.

Mathematical expression is as under:

2/4 = 1/2 that means 50% progeny.