Wyo. Stat. § 14-2-807: Limitation; child having presumed father.

(a) Except as otherwise provided in subsection (b) of this section, a proceeding brought by a presumed father, the mother, or another individual to adjudicate the parentage of a child having a presumed father shall be commenced within a reasonable time after obtaining knowledge of relevant facts, but in no event later than five (5) years after the child's birth.

(b) A proceeding seeking to disprove the father-child relationship between a child and the child's presumed father may be maintained at any time if the court determines that:

(i) The presumed father and the mother of the child neither cohabited nor engaged in sexual intercourse with each other during the probable time of conception; and

(ii) The presumed father never openly held out the child as his own.