The doctors and genetic counselors can use a punnett square in calculating the probability of a child inheriting a disease from the parents. If the genotypes or genetic compositions of the parents are determined, then the chance of the baby having a particular trait will also be determined including the possible illness that might be passed on.
A Punnett square is a diagram of the possible genotypes of an offspring arising from a particular breeding experiment revealing possible combinations of the parents’ gametes that are encapsulated in a tabular format.