Punnett squares help calculate the probability of a child inheriting a specific trait from his parents. The concept of the Punnett square is used in genetics to exhibit simple inheritance patterns between parental generations and their offspring.
Punnett squares are a simple way to showcase the vast number of different genotypes that a child may receive from his parents. The squares combine the genotypes, or genes, of both of the parents to determine the relative number of different genotypes that the children may have. Punnett squares are only able to showcase simple traits because they can only calculate the probability of one gene per square.