The Dravidian kinship system involves selective cousinhood. One's father's brother's children and one's mother's sister's children are "not" cousins but brothers and sisters one step removed. They are considered "consanguineous" ( in Tamil), and marriage with them is strictly forbidden as incestuous. However, one's father's sister's children and one's mother's brother's children are considered cousins and potential mates ( in Tamil). Marriages between such cousins are allowed and encouraged. There is a clear distinction between cross cousins, who are one's true cousins and parallel cousins, who are, in fact, siblings.