(1) An acknowledgment of parentage under RCW 26.26A.200 must:

(a) Be in a record signed by the woman who gave birth to the child and by the individual seeking to establish a parent-child relationship, and the signatures must be attested by a notarial officer or witnessed;

(b) State that the child whose parentage is being acknowledged:

(i) Does not have a presumed parent other than the individual seeking to establish the parent-child relationship or has a presumed parent whose full name is stated; and

(ii) Does not have another acknowledged parent, adjudicated parent, or individual who is a parent of the child under RCW 26.26A.600 through 26.26A.635 and 26.26A.700 through 26.26A.785, other than the woman who gave birth to the child; and

(c) State that the signatories understand that the acknowledgment is the equivalent of an adjudication of parentage of the child and that a challenge to the acknowledgment is permitted only under limited circumstances and is barred four years after the effective date of the acknowledgment.

(2) An acknowledgment of parentage is void if, at the time of signing:

(a) An individual other than the individual seeking to establish parentage is a presumed parent, unless a denial of parentage by the presumed parent in a signed record is filed with the state registrar of vital statistics; or

(b) An individual, other than the woman who gave birth to the child or the individual seeking to establish parentage, is an acknowledged or adjudicated parent or a parent under RCW 26.26A.600 through 26.26A.635 and 26.26A.700 through 26.26A.785.