blood line?

Although I agree with the idea that magick is not passed down by family bloodlines and that everyone can do it to an extent, I am also of the general opinion that there are some who possess a knack or affinity for certain areas or abilities that can be passed down through generations wether by accident or on purpose. For instance Ive heard of families who for four or five generations in a row who have very strong psychic abilities and then the sixth generation couldn't see a spirit if it slapped them in the face.