Step-by-step explanation:
Pedigrees are diagrams that show the phenotype and/or genotype of a person's family members. They are very useful to determine if a certain trait or disease is dominant or recessive, sex-linked or autosomal.
They are extensively used for genetic counseling, because they can reveal the probability that a couple has a diseased child and help them plan accordingly in order to minimize those probabilities and maximize those of having healthy children.