Table 1. Proportion of men born in Sweden 1961–1975 who were convicted of one or more violent offences 1973–2009 and mean general cognitive ability, divided by sibling type.

			Cognitive ability, mean (SD)
	Number of pairs	Violent crime (%)	No violent conviction	Violent conviction	Cognitive ability,sibling correlation
Full brothers	119,195	6.6%	5.2 (1.9)	3.9 (1.7)	0.49
Half-brothers, reared together	8977	13.8%	4.6 (1.8)	3.6 (1.6)	0.33
Half-brothers, reared apart	12,574	14.3%	4.7 (1.8)	3.7 (1.6)	0.24