Oregon Revised Statutes Domestic Relations § 109.175

(1) If paternity of a child born out of wedlock is established pursuant to a petition filed under ORS 109.125 or an order or judgment entered pursuant to ORS 109.124 to 109.230 or ORS 416.400 to 416.465, or if paternity is established by the filing of a voluntary acknowledgment of paternity as provided by ORS 109.070 (1)(e), the parent with physical custody at the time of filing of the petition or the notice under ORS 416.415, or the parent with physical custody at the time of the filing of the voluntary acknowledgment of paternity, has sole legal custody until a court specifically orders otherwise. The first time the court determines who should have legal custody, neither parent shall have the burden of proving a change of circumstances. The court shall give primary consideration to the best interests and welfare of the child and shall consider all the standards set out in ORS 107.137.

(2) In any proceeding under this section, the court may cause an investigation, examination or evaluation to be made under ORS 107.425 or may appoint an individual or a panel or may designate a program to assist the court in creating parenting plans or resolving disputes regarding parenting time and to assist parents in creating and implementing parenting plans under ORS 107.425 (3).