Section 26.26A.115 - Presumption of parentage(1) An individual is presumed to be a parent of a child if: (a) Except as otherwise provided under RCW 26.26A.700 through 26.26A.785, or law of this state other than this chapter:(i) The individual and the woman who gave birth to the child are married to or in a state registered domestic partnership with each other and the child is born during the marriage or partnership, whether the marriage or partnership is or could be declared invalid;(ii) The individual and the woman who gave birth to the child were married to or in a state registered domestic partnership with each other and the child is born not later than three hundred days after the marriage or partnership is terminated by death, dissolution, annulment, declaration of invalidity, or legal separation, whether the marriage or partnership is or could be declared invalid; or(iii) The individual and the woman who gave birth to the child married or entered into a state registered domestic partnership with each other after the birth of the child, whether the marriage or partnership is or could be declared invalid, the individual at any time asserted parentage of the child, and: (A) The assertion is in a record filed with the state registrar of vital statistics; or(B) The individual agreed to be and is named as a parent of the child on the birth record of the child; or(b) The individual resided in the same household with the child for the first four years of the life of the child, including any period of temporary absence, and openly held out the child as the individual's child.(2) A presumption of parentage under this section may be overcome, and competing claims to parentage may be resolved, only by an adjudication under RCW 26.26A.400 through 26.26A.515, or a valid denial of parentage under RCW 26.26A.200 through 26.26A.265.