Copyright © American Speech-Language-Hearing Association From: Heritability of Poor Language Achievement Among Twins J Speech Lang Hear Res. 1998;41(1):188-199. doi:10.1044/jslhr.4101.188 Legend: Scatter plots of composite language scores for sibling pairs wherein the sibling with the lowest score was assigned to the abscissa and the higher scoring sibling was assigned to the ordinate. The top panel contains the data for monozygotic (MZ) twins; the middle panel contains data for the dizygotic (DZ) twins, and the bottom panel contains the data for singleton siblings. Date of download: 10/3/2017 Copyright © American Speech-Language-Hearing Association