The resemblance between these adopted biologically related (N = 106) and
unrelated sibling pairs (N = 230) was compared and examined over time.
Longitudinal Genetic Analysis of Internalizing and Externalizing Problem Behavior in Adopted Biologically Related and
Unrelated Sibling Pairs
Not exact matches
Eight of the birds were
unrelated, and there were three
pairs of
siblings.
The sample for this landmark study included 720
pairs of same - sex adolescent
siblings — including twins, half
siblings, and genetically
unrelated siblings — and their parents.