You're looking for a physiological
cause when the difficulty is with the twisted thinking.

Sure, lots of sex offenders are overweight, but a lot of them are slender and not bad looking. Ted Bundy and Richard Chambers were both good looking. On the other end of the spectrum we have David Carpenter (The Trailside Killer), an overweight man with a severe stutter and a domineering mother, Westley Allan Dodd, a man of small stature and retarded social maturity could only relate to children, or a John Hansen, acne-scarred, skinny and a stutterer.

You see, it isn't their physiological imperfections that makes them what they become but what they think they are in their own twisted minds. Bundy saw himself as a 'bastard' but he also saw himself as entitled at the same time he 'knew' he could never attain those elite co-eds due to his wrong-side-of-the-blanket birth. Chambers, a murderer, ran with a crowd he couldn't financially afford to be a part of and compensated by committing petty crimes to buy drugs for the crowd he aspired to. Hansen, a married man who had a miserable adolescence, became a big game hunter in Alaska. When the thrill of the game hunt palled, he started hunting women. Transported to the Alaskan wilderness in his airplane, he stripped them naked and then let them run in order to hunt them. It made him feel like a 'man.'

Then we have someone like an Edmund Kemper, a large, large man (6'9" and over 250lbs) with an IQ in the genius range. Kemper isn't a handsome man by any means but he isn't a monster, either. He is charming, intelligent and converses well. However, he had a miserable childhood at the hands of his mother, locked in a basement room because she feared he might molest his sisters. But his problems were evident prior to her putting him in the basement since one of his favorite games to play with his sisters was to pretend he was sitting in the electric chair while they pulled the switch. At age 12 or 14 (Can't remember), he shot his grandmother (another domineering woman)in the head because he wondered what it would be like to do it. To keep his grandfather from seeing what he had done to his grandmother, he killed him too.

The twisted pattern of logic (and fantasy) develops early. However, while I don't believe this is the type of criminal that killed JonBenet, I do think we can learn something from studying serial killers and one time offenders. We can learn how they think and many of them do not feel adequate to face their primary target on a one-to-one basis. Such was Edmund Kemper. His primary goal was his mother, but it took 10 murders under his belt before he felt up to confronting her and still he had to go one murder further--killing her best friend--before he turned himself in to the cops.

Killers choose to kill and they do so for their own reasons. Modern science has been trying to show a physiological reason why some people kill for over 100 years. As of yet, nothing has been found. Neither frontal lobe abnormalities nor extra chromosomes have been discovered. I seriously doubt the endocrine system has much to do with it either. And I say this because if it did, there would be some constant trait that would show in every killer's life. Too many Twinkies before the age of six, an all rice diet, beards before age 12, every killer the same height, weight, skin texture, all of them wear glasses, have diabetes, or acne. What has been found is nada, zilch, zero.

They choose to kill because it satisfies something in them.

Rainsong