User blog comment:Theory of everything/Grimm Speculations Part Two: Evolution and Transformation/@comment-4563264-20120422073024

Everyone know what alleles are? Maybe if a Wesen mates with a human, the Wesen gene is a dominant allele and will be passed down. However, a half-breed Wesen has the possibility of breeding a fully human. This will make sense if you've studied genetics. If there's two different Wesen species, then there's a 50% chance it will be one or the other.