How can doctors and genetic counselors calculate the probability of a child inheriting a disease?

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.

The scientist can calculate the probability that a child will inherit an illness using Punnett Square. This technique was created by Reginald Punnett and allowed by means of the genotypes of the parents to determine the possible combination of genotypes that may be possible in the child and in this way calculate the probability that a determined combination of phenotypes generate the disease in the child.