Ala. Code § 26-17-508: Genetic Testing When Specimens Not Available.

(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.