Table 1.

Sibling Correlation in Birth Outcomes

				All Sibs Controlling for ….
Outcome	All Sibs	Brothers	Sisters	Race	Family Income	Parent Educ.	Parent Health	All Factors
Birth Weight	0.528	0.507	0.522	0.500	0.519	0.522	0.512	0.499
	(0.019)	(0.034)	(0.031)	(0.019)	(0.019)	(0.019)	(0.019)	(0.019)
	2995	1529	1466	2995	2995	2995	2995	2995
Gestation	0.377	0.348	0.424	0.377	0.376	0.377	0.377	0.376
	(0.009)	(0.040)	(0.036)	(0.022)	(0.022)	(0.022)	(0.022)	(0.022)
	3145	1601	1544	3145	3145	3145	3145	3145
Health at Birth	0.312	0.321	0.309	0.311	0.309	0.304	0.305	0.298
	(0.023)	(0.040)	(0.039)	(0.023)	(0.023)	(0.023)	(0.023)	(0.023)
	3223	1644	1579	3223	3223	3223	3223	3223
Poor Health at Birth	0.121	0.184	0.081	0.121	0.120	0.118	0.121	0.117
	(0.027)	(0.046)	(0.044)	(0.027)	(0.027)	(0.027)	(0.027)	(0.027)
	3223	1644	1579	3223	3223	3223	3223	3223
NICU	0.184	0.194	0.192	0.184	0.180	0.180	0.180	0.177
	(0.027)	(0.052)	(0.046)	(0.027)	(0.027)	(0.027)	(0.027)	(0.027)
	3215	1640	1575	3215	3215	3215	3215	3215