In humans, hair colour is an autosomal trait such that brown hair is dominant over blonde hair. Goltz Syndrome is an X-linked dominant disorder characterized by abnormal development of the skin, eyes, hands, and feet.
A blonde woman who does not have Goltz Syndrome has children with a heterozygous brown-haired man who has Goltz Syndrome.
Determine the probability that if they have a son, he will have brown hair and not have Goltz Syndrome.