The one-child family and violent criminality: a 31-year follow-up study of the Northern Finland 1966 Birth Cohort.
OBJECTIVE
Serious defects in social skills acquired during childhood may be associated with aggressive behavior in later life. The authors studied whether being an only child was associated with criminality in adulthood and, secondly, if parental factors increased the putative risk.


METHODS
The authors used an unselected, prospectively collected large birth cohort. Data on crimes were linked with being an only child as well as with perinatal risk and maternal and paternal psychological risk factors among male subjects.


RESULTS
The risk for violent crimes later in life was elevated among the only children. If perinatal or parental risks were combined with being an only child, the odds ratios for violent offending increased four-fold to eight-fold. A corresponding risk increase between being an only child and nonviolent offending was not detected.


CONCLUSIONS
These results support the hypothesis that growing up as an only child is associated with violent criminality among male subjects.
Kemppainen
L
L
Department of Psychiatry, University of Oulu, Peltolantie 5, 90210 Oulu, Finland. liisa.kemppainen@oulu.fi
Jokelainen
J
J
Järvelin
M R
MR
Isohanni
M
M
Räsänen
P
P
D000293:Adolescent; D000328:Adult; D000987:Antisocial Personality Disorder / Q000453:epidemiology; D002648:Child; D016241:Child of Impaired Parents / Q000523:psychology; D015331:Cohort Studies; D003417:Criminal Psychology; D005195:Family Relations; D005260:Female; D005387:Finland / Q000453:epidemiology; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008423:Maternal Age; D016017:Odds Ratio; D009863:Only Child / Q000523:psychology* / Q000706:statistics & numerical data; D010287:Parent-Child Relations; D010333:Paternal Deprivation; D012307:Risk Factors; D012737:Sex Factors; D014754:Violence / Q000523:psychology / Q000706:statistics & numerical data*