Incest
The exact definition of the incest relationship varies. In some societies it is immediate relations, such as parents and their children; or brothers and sisters of the same parents. It sometimes includes extended family like aunts, nephews, nieces and uncles. That way, intercourse between cousins is legally permitted in the large majority of the world, but is disliked in many countries. In some U.S. states, such as Texas, the legal definition of incest includes first cousins, but not second cousins. A person who engages in incest may be called an incestophile or incestualist.