The psychiatric community's understanding of pedophilia has changed in the past several decades. What used to be seen as a treatable disorder -- and by many faiths as a serious moral sin -- is now seen as both a possibly incurable compulsion, and a crime. To make matters more complicated, pedophilia, an attraction to pre-pubescent children, seems to differ in its roots and prognosis from ephebophilia, an attraction to adolescents. In the following two pieces, experts who work in the field explain the complicated nature and our evolving understanding of child sexual abuse.