Multiple Alleles

Some traits are coded for by more than two alleles.

Example:
In humans, there are four types of blood: type A, type B, type AB, and type O. The alleles A and B are codominant to each other and the O allele is recessive to both A and B. In the 1950s a young woman sued Charlie Chaplin for parental support of her illegitimate child. Charlie Chaplin's blood type was on record as type AB (ab). The mother of the child had type A (ao) and her son had type O blood (oo). Based on blood type, could the child have been Charlie Chaplin's?

Image by Chernobyl Frog Dissections