Senate Bill 2539 amends Tennessee Code Annotated to enhance the legal framework surrounding child custody and the consideration of a child's best interest in custody determinations. The bill introduces new subsections to Title 36-6-106, which clarify that the doctrine of res judicata does not prevent the admission of evidence regarding a parent's or caregiver's past conduct if it is relevant to the child's best interest. This evidence can include a wide range of documentation, such as sworn testimony, medical records, and reports from child protective services. Additionally, the bill mandates that courts give the highest weight to credible evidence of physical abuse, sexual abuse, or domestic violence when determining a child's best interest.

Furthermore, the bill establishes a presumption that placing a child with a parent found to have committed physical abuse, sexual abuse, or domestic violence is not in the child's best interest. If a court decides to place a child with such a parent, it must provide written findings explaining why this presumption is rebutted. The court is also required to review any available protective services records related to the child before making its custody determination. This legislation aims to strengthen protections for children in custody cases by ensuring that evidence of abuse is thoroughly considered.