House loves his mother but hates his father, who he claims has an "insane moral compass", and deliberately attempts to avoid both parents. At one point (episode One Day, One Room), House tells a story of his parents leaving him with his grandmother, whose punishments constituted abuse. However, he later confesses it was his father who abused him. Due to this abuse, House never believed John was his biological father; at the age of 12, he inferred that a friend of the family with the same birthmark as himself was his real father. In the episode "Birthmarks", House discovers that John is not his biological father after ordering a DNA test. After a second DNA test was performed in the episode "Love is Blind", House discovers that the man he assumed to be his biological father, Thomas Bell, was not either. The identity of his real father remains unknown.