The aim of this longitudinal sibling adoption study was to estimate genetic
and environmental components of variance in parent- and child-reported mea
sures of the family environment (parental negative affect, negative control
, and achievement orientation). Participants included 85 adoptive and 106 n
onadoptive sibling pairs from the Colorado Adoption Project. Parents and ch
ildren completed annual assessments of the family environment when the chil
dren were 10, 11, and 12 years old, and genetic and environmental parameter
estimates were derived. Genetic influences were found for parent-reported
negativity and warmth and child-reported achievement orientation, suggestin
g child genetic effects on these measures of the family environment. Shared
environmental influences were found for parent-reported negativity, incons
istent discipline, warmth, and child-reported positivity. Nonshared environ
mental variance was substantial for children's ratings, but modest for pare
nts' ratings.