Board Thread:General Grimm Discussion/@comment-78.72.160.162-20150328122307/@comment-71.121.198.236-20150328144134

Just because one of your parents is a Grimm doesn't mean your guaranteed to be a Grimm yourself. Nick's maternal grandfather was a Grimm, as were his daughters (Nick's mother and aunt), but not his son (Nick's uncle). In short you get Grimm powers or you don't; it's a hit or miss.