In some custody disputes parents are equally fit, other factors are not decisive, shared custody is ruled out, and the parental conflict is the only threat to children's well-being. There are no systematic principles to resolve these disputes. To fill this gap, I introduce the equality principle. Following splitting the difference and goal-setting theory, parents renegotiate under threat of randomization. If renegotiation fails, their chances of winning are equal. This principle may improve children's well-being, parental behavior, court efficiency, and custody investigations. The principle is discussed in terms of child perspective, appellate rights, applicability, irrationality, and attorney effects on negotiations. Key Points for the Family Court Community: _ The equality principle is a strategy to motivate litigating parents to agree about custody, living, or visitation disputes. _ Compared to the present system, the equality principle is beneficial because. Children spend less time in harmful uncertainty,. Parents are incentivized to behave more rationally and generously,. Courts and parents save resources,. Custody evaluations are improved as irrelevant differences between parents are ignored, and. Judges are less emotionally strained to make important decisions based on insufficient information.