<< If you could point to any source of information
 >that might shed some light on the issue, it would be much appreciated.
  >>

There's a book called "High Risk: Children Without A Conscience," by Dr. Ken
Magid, that shines a lot of light on the subject. In a nutshell, he pointes
out how children deprived of the nurturing they need the first few years of
life when they are the most helpless and defenseless causes them to grow up
"without a conscience."
FWIW.
gc