In general, a child cannot legally decide which parent to live with unless they are emancipated or reach the age of majority.
However, let us assume that parties in a divorce are dealing with a custody and parenting time dispute related to a 16-year old child. The parties (through counsel) can formulate a parenting plan that says, for example, that the parties intend on following a set schedule, but that they recognize and appreciate the age of the child and will allow the child to dictate their schedule.
In this example, issues can arise related to enforcement of the parenting time schedule, but nevertheless, it is a plan that allows for a teenager to dictate which parent they want to be with.
Another option is hiring an attorney for the minor. In Oregon, courts do not want children to testify in a dispute between parents. An attorney for the child will allow the court to understand the child’s position, without needing the child to testify.