Grimm

It was revealed at Comic Con that actual descendants of the Brothers Grimm reside in Portland. The producers had no idea until a member in the audience told them.

Each episode opens with a quote from various fairytales or folk stories, which relate to the episode in some way.

According to Kelly Burkhardt, the Grimm trait is not strictly hereditary. Some offspring of Grimms have it and others don't. Girls also realize it earlier than boys.