Further, formalizing same-sex marriage signals to the public that fathers and mothers are interchangeable (that is, that two fathers and two mothers are equivalent to having both a father and a mother). Whether intended or not, this ultimately signals that both fathers and mothers are also expendable. If public policy treats both fatherhood and motherhood as expendable goods in the lives of children, this will weaken the public expectation that both fathers and mothers stick with the family and remain present in the lives of their children. The idea that fathers are fundamentally needed by their children (and their mother) promotes marital fidelity and permanence.