What is Incest? A relationship is incestuous if people related by blood or adoption are in an intimate, sexual relationship. Is it a Crime? Yes, it is. In the United States, incestuous relations are generally considered a crime that is punishable by law. Incestuous marriages are illegal in all the states of the United States. Despite this, not all states have laws against incestuous relationships and these incestuous relationships may continue to take place. Texas Laws on Incest In Texas, incestuous relation is a crime. In fact, it is an act of prohibited sexual conduct. It must involve the penetration […]