Board Thread:General Discussion/@comment-6677347-20131227002040/@comment-283842-20150417225052

In one of the episodes Nick was explaining the inheritance pattern of being a Grimm. He said from what he can tell, it is a recessive trait. Meaning in order to be a Grimm, you have 2 "Grimm Alleles" which means you have to inherit one "Grimm allele" from each parent.

If two Grimms have children, all of their children will become Grimms.

If a Grimm has a child with a normal human that is a carrier of the "grim allele" - 50% of the children will be Grimm's and 50% will be normal (but carry the grimm allele).

If two normal humans that are both carriers of the Grimm allele have children, 25% will be Grimms, 50% will be unaffected carriers, 25% will be normal humans (non-carriers).

My point is this, if a Grimm and a Wesen have a child - that  child will be a carrier of the grimm allele, but will not be a Grimm. Because the Wesen could not pass on the Grimm allele to the child (and you need 2 copies to become a Grimm). The Wesen would have to be a carrier of the grimm allele, which is impossible unless the Wesen had a Grimm in its ancestory. The child of a Grimm and Wesen would be a Carrier of the Grimm Allele, and could potentially pass on that allele to the next generation to make a Grimm.