paedophiles may have been exposed to pre-birth conditions that affected their physical development.
For the study, the researchers observed this height difference by analysing the files of over 1,000 men who were assessed for paedophilia or other sexual disorders between 1995 and 2006 at the Kurt Freund Laboratory in Toronto, Canada.
A difference in average height is a trait found in other illnesses with biological links. The average difference in height was two centimetres, which is similar to the shorter height associated with schizophrenia or Alzheimer's disease.
Researchers have said that further research is necessary, but this finding re-enforces evidence that pedophilia has a biological cause, possibly related to brain development before birth.
'This research does not mean that pedophiles are not criminally responsible for their behaviour but the discovery of biological markers for pedophilia has important implications for future study and possibly treatment,' said Dr. James Cantor, CAMH Psychologist and lead researcher on the study.
The new study adds to previous research from this team that found pedophiles have lower IQs, are three times more likely to be left-handed, failed school grades significantly more frequently, and suffered more head injuries as children.
The study is published in Sexual Abuse: A Journal of Research and Treatment