T.D. (plaintiff) filed a petition in Louisiana against M.M.M. (defendant) for divorce after approximately seven years of marriage. During the marriage, T.D. had a protracted affair with P.W. that resulted in the birth of a son, C.M. P.W., who suspected that he was the biological father of C.M., regularly visited C.M. with T.D.’s consent. P.W.’s suspicions were later confirmed by a positive paternity test. When T.D. and M.M.M. separated, P.W. scaled back his visits with C.M. at T.D.’s request. Subsequently, T.D. and M.M.M. were granted a divorce. The trial court granted legal and physical custody of C.M. to T.D. and visitation rights to M.M.M. Shortly thereafter, T.D. ended the affair with P.W. and would not allow P.W. to have access to C.M. P.W. intervened in the custody proceedings by filing an avowal action to be declared the biological father of C.M. T.D. and M.M.M. objected to P.W.’s intervention. The trial court recognized P.W. as the biological father of C.M., ordered a hearing to resolve visitation and child-support issues, and ordered a mental-health evaluation of C.M. to assess whether there were any possible detrimental effects to the child resulting from the court’s finding. T.D. and M.M.M. appealed, arguing that P.W.’s action was barred by the doctrine of laches. The court of appeals agreed and reversed the judgment of the trial court. P.W. appealed. The Supreme Court of Louisiana granted certiorari to review.