. Author manuscript; available in PMC: 2013 Mar 1.

Published in final edited form as: Behav Genet. 2011 Sep 7;42(2):245–255. doi: 10.1007/s10519-011-9500-3

Table III.

Bivariate Heritability at the Extremes of the General Population

Selection Variable	Sex and Zygosity	N (probands)	Transformed Means					Bivariate Heritability Estimates		>95% Genetic Correlations
Selection Variable	Sex and Zygosity	N (probands)	Proband	Cotwin	Proband	Cotwin		Outcome Variable
			CI		RRBI			Outcome Variable
SI	MZM	121	0.58	0.48	0.44	0.36		CI	RRBI	SI-CI
SI	DZM	135	0.51	0.14	0.41	0.13	Males	0.48^* (0.23, 0.48)	0.36^* (0.10, 0.36)	0.66
	MZF	54	0.51	0.36	0.36	0.23	Males	0.48^* (0.23, 0.48)	0.36^* (0.10, 0.36)	0.66
	DZF	53	0.50	0.27	0.41	0.04	Females	0.17 (0.00, 0.36)	0.23^* (0.00, 0.23)	0.24
			SI		RRBI					SI-RRBI
CI	MZM	121	0.61	0.49	0.57	0.47		SI	RRBI	SI-RRBI
	DZM	123	0.51	0.15	0.57	0.17	Males	0.49^* (0.24, 0.49)	0.47^* (0.17, 0.47)	0.44
	MZF	99	0.35	0.24	0.57	0.46	Males	0.49^* (0.24, 0.49)	0.47^* (0.17, 0.47)	0.44
	DZF	83	0.35	0.16	0.53	0.26	Females	0.15 (0.00, 0.24)	0.40 (0.08, 0.46)	0.29
			SI		CI					CI-RRBI
RRBI	MZM	147	0.41	0.33	0.51	0.41		SI	CI	CI-RRBI
	DZM	133	0.40	0.19	0.52	0.19	Males	0.28 (0.06, 0.33)	0.41^* (0.17, 0.42)	0.58
	MZF	120	0.20	0.15	0.50	0.44	Males	0.28 (0.06, 0.33)	0.41^* (0.17, 0.42)	0.58
	DZF	118	0.19	0.05	0.43	0.21	Females	0.15^* (0.00, 0.15)	0.44^* (0.18, 0.44)	0.57

Note: SI=social impairment; CI=communication impairment; RRBI=restricted and repetitive behaviors and interests; MZM=monozygotic male; MZF=monozygotic female; DZM=dizygotic male; DZF=dizygotic female; H²g=group heritability; see text for description of transformed means; 95% CI= 95% confidence interval; standard errors adjusted for number of twin pairs with 2 probands.

h_g² constrained to sex-specific MZ transformed cotwin mean.