During a two-year relationship, Michael Holt (plaintiff) and Laurie Holt (defendant) had a child, C.H. Michael and Laurie separated three years later without marrying. Subsequently, Laurie became engaged to another man, who was killed in a work-related accident when she was three-months pregnant with his child, B.M.H. Michael supported Laurie before, during, and after B.M.H.’s birth. Michael and Laurie were briefly married, but soon divorced. A parenting plan gave primary physical custody of C.H. to Laurie and visitation rights to Michael every other weekend. The plan did not include provisions for B.M.H., but Michael and Laurie agreed that B.M.H. would follow the same custody and visitation plan as C.H. Michael was highly active in B.M.H.’s life and held himself out as B.M.H.’s father in all respects. Laurie even changed B.M.H.’s last name to Holt. Later, Laurie planned to move 50 miles away. Michael filed a petition for non-parental custody of B.M.H., requesting that the court declare him to be B.M.H.’s de facto parent. The trial court appointed a guardian ad litem (GAL) to represent the interests of B.M.H. After a hearing, the court held that Michael had made a prima facie case for de facto parentage. Subsequently, the Supreme Court of Washington decided In re Parentage of M.F., 228 P.3d 1270 (Wash. 2010), holding that a former stepfather could not be his stepchild’s de facto parent. The trial court conducted several hearings to determine the impact of M.F. on the de facto action. The trial court dismissed Michael’s de facto parentage claim but, based on the GAL’s testimony and report, found good cause to proceed on Michael’s non-parental custody petition. Laurie appealed. The court of appeals reinstated the de facto parentage petition and affirmed the trial court’s order for a show-cause hearing on the non-parental custody petition. The Supreme Court of Washington granted certiorari to review.