Section 531. Hearing

The trial shall be by the court without a jury. The
  mother or the alleged father shall  be  competent  to  testify  but  the
  respondent  shall  not be compelled to testify. If the mother is married
  both she and her husband may testify to  nonaccess.  If  the  respondent
  shall  offer  testimony of access by others at or about the time charged
  in the complaint, such testimony shall not be competent or admissible in
  evidence except when  corroborated  by  other  facts  and  circumstances
  tending  to  prove such access. The court may exclude the general public
  from the room where the proceedings are heard and may admit only persons
  directly interested in the case, including officers  of  the  court  and
  witnesses.