I don’t think this has anything at all to do with parentage. Lanza was just nuts in a clinical way. The statements by former teachers that he couldn’t feel pain and would burn himself and not feel a thing lead me to believe he had far more serious mental problems than what is reported. There may have been undiagnosed schizophrenia, hereditary sensory and autonomic neuropathy, or a combination of disorders.
And you think that a father being gone from his life for years had nothing to do with his mental problems?
I can tell you from my own interactions with young men and women is that the kind of numbness described in Mr. Lanza is often caused by personal trauma. Is it not possible that his father walking out of the home contributed to this kind of mental trauma?