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

HD 4103 amends Massachusetts law to clarify how courts determine custody and parenting arrangements for children in family court cases. It defines key terms like "shared decision-making responsibility" (both parents making major decisions) and "shared residential responsibility" (child spending significant time with both parents), replacing previous terms. The bill requires courts to prioritize the child's best interest using specific factors - such as the child's relationship with each parent and school adjustments - without presuming either shared or sole custody. It mandates detailed parenting plans covering education, healthcare, dispute resolution, and schedules, while ensuring child support follows existing guidelines regardless of custody type. This directly affects parents, judges, and family court proceedings involving child custody in Massachusetts.