A method for predicting the ratios of phenotypes in offspring, given the phenotypes and/or genotypes of the parents. Generally, the alleles of two or fewer genetic loci are worked with per square. Here is an example of a Punnet square: X Y X° X°X X°Y X XX XY In this example, we see the theoretical offspring of a woman with genotype X°X (X° being an X chromosome carrying an X-linked recessive gene for baldness; this woman is not bald but is a carrier for the gene) crossed with a normal man (genotype XY). By using this square, we find that this pairing has a: 25% chance of producing a non-bald, non-carrier daughter 25% chance of producing a non-bald, carrier daughter 25% chance of producing a bald son 25% chance of producing a non-bald son Now, let's change the square slightly; we'll using the same gene, but with a carrier woman (X°X) crossed with a bald man (X°Y): X° Y X° X°X° X°Y X XX° XY In this square, we see that this pairing has a: 25% chance of producing a bald daughter 25% chance of producing a non-bald, carrier daughter 25% chance of producing a bald son 25% chance of producing a non-bald son