AAHHH Super beagle, stop putting words into my mouth!
I didn't say all psycopaths weren't raised in loving homes, or that all psycopaths have the same brain.
I said that the documentary highlighted an interesting thing, that there was a genetic predisposition found amongst the whole population, but more prevelant in psycopaths, but that it didn't always develop into psycopathic tendencies and that was probably down to nuture. By the same token, someone raised in a loving home with that brain type may (please note the MAY) develop psycopathic tendencies DESPITE his wonderful nurture.
I used the documentary as an example of the interaction between nature and nuture.
I said very clearly that this is an example of the complex interaction between our genes and our environment. Most of which we know nothing about. We have no idea for the most part what our genes have within them.
It is possible that my genes have a load of stuff that I might POTENTIALLY do, or illnesses that I might potentially have.
None of that is rocket science and is pretty might agreed upon, eg, I inherit my Mum's low blood pressure, or I inherit my Dad's tendency to type 1 diabeties. We know that there is loads of stuff that is in our genes as potentials. Why would it be any different with mental health or personality?
How much can I influence which of those many genes is active? Not an easy question to answer, as there hasn't been enough research. In terms of health it is quite well docmented. I think that for example your likelyhood of living a long life is predictable by looking at your parents and grandparents and how long they lived. Even taking lifestyle choices into consideration the geneitcs is by far the strongest predictor. But if I then chose to smoke 40 a day, I am sabotaging my 'good health' genes.