http://www.rainn.org/types-of-assault/sexual-assault/incest.html
Rape, Abuse and Incest National Network
Incest is considered by many experts to be a particularly damaging form of sexual abuse because it is perpetrated by individuals whom the victim trusts and depends upon. In addition, support can also be lacking and pressure to keep silent powerful as fear of the family breaking up can be overwhelming to other family members. This fact sheet provides background information on incest and reviews common reactions, including reactions in children, stigmatization, and powerlessness.