(a) Subject to subsection (b), if a genetic-testing specimen is not available from an individual who may be the mother or the father of a child, for good cause and under circumstances the court considers to be just, the court may order the following individuals to submit specimens for genetic testing:
(1) the parents of the individual;
(2) brothers and sisters of the individual;
(3) other children of the individual and their other parent; and
(4) other relatives of the individual necessary to complete genetic testing.
(b) Issuance of an order under this section requires a finding that a need for genetic testing outweighs the legitimate interests of the person sought to be tested.