(1) If scientific, technical or other specialized knowledge will assist the trier of fact in understanding the testimony of a child under the age of twelve (12) in a case in which the occurrence or non-occurrence of physical or sexual abuse of a child is a material issue, a witness qualified as an expert by knowledge, skill, experience, training or education, may testify, based on such expertise, in the form of an opinion or otherwise.

(2) The facts or data in the particular case upon which such an expert bases an opinion or inference may be those perceived by or made known to him at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences about the occurrence or non-occurrence of physical or sexual abuse of children, or about children who may be victims or observers of such abuse, the facts or data need not be admissible in evidence.

(3) Testimony in the form of an opinion or inference otherwise admissible is not objectionable because it embraces an ultimate issue to be decided by the trier of fact.

(4) The expert may testify in terms of opinion or inference and give his reasons therefor without prior disclosure of the underlying facts or data, unless the judge requires otherwise. The expert may in any event be required to disclose the underlying facts or data on cross-examination.

(5) The court, in a case where the occurrence or non-occurrence of physical or sexual child abuse is a material issue, may on its own motion or on the motion of any party enter an order to show cause why expert witnesses should not be appointed, and may request the parties to submit nomination. The court may appoint any expert witnesses agreed upon by the parties, and may appoint witnesses of its own selection. An expert witness shall not be appointed by the court unless he consents to act. A witness so appointed shall be informed of his duties by the court in writing, a copy of which shall be filed with the clerk, or at a conference in which the parties shall have opportunity to participate. A witness so appointed shall advise the parties of his findings, if any; his deposition may be taken by any party; and he may be called to testify by the court or any party. He shall be subject to cross-examination by each party, including a party calling him as a witness.

(6) In the exercise of its discretion, the court may authorize disclosure to the jury of the fact that the court appointed the expert witness.

(7) Nothing in this subsection limits the parties in calling expert witnesses of their own selection.