A family can be tied together by blood and by legal adoption. The traditional nuclear family is tied together by blood. The legal adoption of minor children by adults in a legal union, whether by marriage or a legal agreement, is considered along the same lines as the biological connection. However, it can be argued that a nuclear family can be formed by choice and love, instead of biological connections. A good example of this is when the mother and father of the children divorce and both remarry other people. The children are assimilated into the new families