Feminism is a powerful and increasingly pervasive perspective, but it does not offer a theory that is predictive or capable of being tested in the normal manner. The family systems perspective clarifies family experiences that shape and sustain abusive behavior, but additional concepts are needed to explain why one abused child becomes an abuser and another does not. Psychodynamic views sometimes provide a useful perspective on a youth's behavior, although they have limited value and their empirical status is questionable. Psychological perspectives include functional analysis and the diathesis-stressor paradigm, which is perhaps the most important current approach used by psychologists in considering all forms of abnormal behavior. Its essential idea is that all abnormal behavior is the outcome of the interaction between personal vulnerability factors and external stressors. Developmental issues are also a core element of psychologists' approach to abusive behavior. Learning theory is the overarching theoretical approach used by psychologists to understanding and explaining abusive behavior; it focuses on three learning processes: classical conditioning, operant conditioning, and social learning. Finkelhor's model encompasses emotional congruence, sexual arousal to children, blockage, and disinhibitions. Whether sexually abusive acts differ fundamentally from other deviance is still debatable. The available data suggest the need to regard sexually abusive behavior as a variant of deviant acts against the person until good evidence exists to the contrary.