An Act relative to determining the best interest of children in probate & family court

This bill updates Massachusetts law to clarify how courts should define and apply the concept of a child's best interest in family and probate cases. It introduces specific definitions for shared versus sole decision-making and residential responsibilities, requiring parents to submit detailed parenting plans that outline schedules for education, healthcare, and dispute resolution. The legislation removes previous legal presumptions favoring shared custody, instead mandating that judges make orders based on the unique circumstances of each case without assuming one arrangement is better than the other. Additionally, it establishes a temporary rule granting both parents equal legal custody at the start of a case unless there is evidence of abuse or neglect, while requiring written justification if a judge orders shared responsibility despite existing protective orders.