The neglected middleborn hypothesis predicts that middleborn children
should have a worse relationship quality with their parents compared to
firstborn and lastborn children. However, prior studies investigating
this question have produced mixed results. In this study, the neglected
middleborn hypothesis was tested using a large-scale, population-based
sample of younger adults from Germany. Relationship quality was measured
by contact frequency, emotional closeness, intimacy and amount of
conflict participants reported towards their mothers and their fathers.
It was found that middleborns reported less intimacy towards their
mothers than lastborns. However, in all other cases, middleborns did not
differ from firstborns or lastborns in their relationship quality with
their mothers and fathers. Thus, the study did not find convincing
support for the neglected middleborn effect.