Many stepparents think they can exile absent, out-of-touch, disengaged bio-parents into a forgotten past, while their stepchildren often feel as if they have a hole in their heart where the real dad or mom ought to be. This sense of loss and possibly a loyalty bind ("If I love my stepparent, will I lose whatever shreds of my true father that remain to me?") frequently lies dormant until the stepchild reaches adolescence—a phenomenon known as the "sleeper effect." Then, as research studies have shown, previously well-adjusted stepchildren will often experience a huge upsurge of conflicted, upsetting feelings.
The abrupt awakening of these feelings of loss and divided loyalties is probably due to cognitive, intellectual and hormonal changes; as well as to the developmental challenge of the adolescent years—that of forging an authentic identity. As a result, however, the stepchild may become a rebel without an obvious cause: volatile, rebellious and angrily rejecting of her loving, caring stepparent.