New York policy regarding forensic evaluations of the parties and their children in custody cases has evolved slowly since the 1960s when traditional adversary procedure was adapted in Kesseler v. Kesseler, 10 N.Y.2d 445, 225 N.Y.S.2d 1 (1962)), to serve the "best interests of the child." 

In Kesseler v. Kesseler, supra, the court of appeals held that in a custody proceeding, the court may order forensic evaluations by impartial professionals who would be available to be called as an expert witness and testify in accordance with the common-law rules of evidence. The court held that even without the consent of the parties, the court may direct a probation officer, family counselor attached to the court, or other qualified and impartial psychiatrists, psychologists, or other professional medical personnel to make investigations, although they may not report to the court. The report could be used to furnish leads for the introduction of common-law evidence. The court of appeals went on to state that there was no reason which would prevent the court, in the proper exercise of judicial discretion, from calling upon such persons "to examine the infant or to examine the parents also if they will submit to such examination. However, the psychologists, psychiatrists, or other medical personnel could not report to the court in the absence of a stipulation by the parties. 

In Family Court custody proceedings, it became customary for the court to order mental health examinations under Family Court Act Section 251, conducted by clinicians on the staff of the Family Court Mental Health Services Clinic or by another mental health expert, such as one selected and agreed to by both parties. Family Court Act Section 251 provides, in part: "After the filing of a petition under this act over which the family court appears to have jurisdiction, the court may cause any person within its jurisdiction and the parent or other person legally responsible for the care of any child within its jurisdiction to be examined by a physician, psychiatrist or psychologist appointed or designated for the purpose by the court when such an examination will serve the purposes of this act …" Under Family Court Act Section 251, the Family Court could sua sponte order the examinations or order them in response to a motion by one of the parties.