House Bill 1845 amends Tennessee law to establish requirements for expert evaluations in contested legal proceedings involving children, specifically in cases where a guardian ad litem (GAL) is appointed. The bill mandates that the court order an evaluation by at least one qualified expert, unless it finds that such an examination is unnecessary for determining the child's best interests. The evaluations must be conducted by licensed professionals, including medical doctors, psychiatrists, psychologists, licensed clinical social workers, and licensed professional counselors, among others. The expert is required to submit a sworn written report detailing the child's medical and psychological history, current condition, and any recommendations for further evaluation or treatment.

Additionally, the bill stipulates that the expert report serves as prima facie evidence regarding the child's condition and relevant factors for determining their best interests, which can be challenged by competent evidence. The GAL must consider the expert's findings when making recommendations, and if there is a significant deviation from the expert's conclusions, the GAL must provide a written explanation. The costs of the evaluations will be allocated among the parties based on their ability to pay. This legislation aims to enhance the protection of children's welfare in legal proceedings by ensuring thorough evaluations are conducted when necessary.