“…Second, many studies rely primarily on small, male-only, non-representative samples, or employ no comparison groups, thus raising questions about the generalizability of any observed family size and delinquency relationship. For example, reliance on male-only samples is common (Biles & Challinger, 1981; Farrington, 1987; Farrington et al, 2009; Glueck & Glueck, 1950; Heck & Walsh, 2000; Lees & Newson, 1954; Parrott & Strongman, 1984; Sampson & Laub, 1994; Slawson, 1925; Walsh & Petee, 1987; West & Farrington, 1973), and many studies focus exclusively on known delinquents (Andrew, 1978; Biles & Challinger, 1981; Heck & Walsh, 2000; Lees & Newson, 1954; Muola et al, 2009; Touliatos & Lindholm, 1980). The generalizability of the study findings thus remains unclear.…”