(1) A proceeding to determine whether an alleged genetic parent who is not a presumed parent is a parent of a child may be commenced:

(a) Before the child becomes an adult; or

(b) After the child becomes an adult, but only if the child initiates the proceeding.

(2) Except as otherwise provided in RCW 26.26A.465, this subsection applies in a proceeding described in subsection (1) of this section if the woman who gave birth to the child is the only other individual with a claim to parentage of the child. The court shall adjudicate an alleged genetic parent to be a parent of the child if the alleged genetic parent:

(a) Is identified under RCW 26.26A.325 as a genetic parent of the child and the identification is not successfully challenged under RCW 26.26A.325;

(b) Admits parentage in a pleading, when making an appearance, or during a hearing, the court accepts the admission, and the court determines the alleged genetic parent to be a parent of the child;

(c) Declines to submit to genetic testing ordered by the court or a child support agency, in which case the court may adjudicate the alleged genetic parent to be a parent of the child even if the alleged genetic parent denies a genetic relationship with the child;

(d) Is in default after service of process and the court determines the alleged genetic parent to be a parent of the child; or

(e) Is neither identified nor excluded as a genetic parent by genetic testing and, based on other evidence, the court determines the alleged genetic parent to be a parent of the child.

(3) Except as otherwise provided in RCW 26.26A.465 and subject to other limitations in RCW 26.26A.400 through 26.26A.515, if in a proceeding involving an alleged genetic parent, at least one other individual in addition to the woman who gave birth to the child has a claim to parentage of the child, the court shall adjudicate parentage under RCW 26.26A.460.