(a) Child. Mental or physical examination of a child may be obtained as provided by law.
(b) Parent, Legal Custodian, or Other Person who has Custody or is Requesting Custody. At any time after the filing of a shelter, dependency, or termination of parental rights petition, or after an adjudication of dependency or a finding of dependency when adjudication is withheld, when the mental or physical condition, including the blood group, of a parent, legal custodian, or other person who has custody or is requesting custody of a child is in controversy, any party may request the court to order the person to submit to a physical or mental examination or a substance abuse evaluation or assessment by a qualified professional. The order may be made only on good cause shown and after notice to the person to be examined and to all parties and shall specify the time, place, manner, conditions, and scope of the examination and the person or persons by whom it is to be made. The person whose examination is sought may, after receiving notice of the request for an examination, request a hearing seeking to quash the request. The court may, on its own motion, order a parent, legal custodian, or other person who has custody or is requesting custody to undergo such evaluation, treatment, or counseling activities as authorized by law.