PolyPatEx addresses the question - at a given locus, can the candidate father provide a viable gamete given its allele set, and given the possible paternal gametes indicated by the progeny's and mother's allele sets?
Note that PolyPatEx does not implement a probabilistic solution to the exclusion problem, merely a simple comparative analysis based on available alleles and their multiplicities. Also note that PolyPatEx is not optimised for very large marker datasets such as SNP datasets, instead is suited to low density, high information markers such as SSRs.