Surely what happens during a person's childhood isn't the sole determinant of their personality later in life. Environment and life experiences are important as well -- someone who was formerly amiable and trusting may become withdrawn and recluse as a result of a traumatizing incident.
There could also be the argument that a child's disposition (attachment style) is genetically determined, but this could be affected by the parents' treatment of the child. If the child is naturally a "secure" baby but the parents are abusive or neglectful, the child most likely won't display "secure" attributes later in life.
