(a) Upon petition of the defendant in a paternity proceeding where the defendant has been declared the legal father, the case shall be reopened if there is scientific evidence presented by the defendant that he is not the father. The court shall admit into evidence any scientific test recognized by the court that has been conducted in accordance with established scientific principles or the court may order a blood test, or a Deoxyribose Nucleic Acid test of the mother, father, and child. Whenever the court orders a test and any of the persons to be tested refuse to submit to the test, the fact shall be disclosed at the trial, unless good cause is shown.
(b) The test shall be made by a qualified expert approved by the court. The expert may be called by the court or any party as a witness to testify to the test results and shall be subject to cross-examination by the parties. The test results may be admitted into evidence. If more than one test is performed and the results are conflicting, none of the test results shall be admissible as evidence of paternity or nonpaternity.
(c) Compensation of the expert witness shall be paid by the petitioner.
(d) In the event the child has been adopted the matter of paternity may not be reopened under this chapter.