The concentration of offending in families

Abstract

In the Cambridge Study in Delinquent Development, 411 London males from 397 families of origin have been followed up from age eight to age 32 by interviews, and from age 10 to age 40 in records. This paper relates convictions of these males to convictions of their biological fathers and mothers, full brothers and sisters, and wives. Overall, 601 out of 2203 birth family members were convicted (1.5 convicted persons on average out of 5.5 persons per family). While 64 per cent of the families contained at least one convicted person, only 6 per cent of the families accounted for half of all the convictions. Convictions of one family member were strongly related to convictions of every other family member. In both generations, the majority of convicted mothers mated with convicted fathers. About three‐quarters of convicted fathers and convicted mothers had a convicted child, and about three‐quarters of families containing convicted daughters also contained convicted sons. Same‐sex relationships within generations and between generations were stronger than opposite‐sex relationships. Convictions of older siblings were more strongly related to convictions of the Study male than were convictions of younger siblings. Convictions of each family member were independendy related to convictions of the Study male. Very little of the association between convictions of family members was attributable to co‐offending. It is concluded that offending is strongly concentrated in families and tends to be transmitted from one generation to the next; however, this research does not establish the precise mechanism of transmission (genetic or environmental).