concurring.
In this case, the defendant, an anesthesiologist, is being sued for malpractice in the death of an infant under the Wrongful Death Act, N.J.S.A. 2A:31-1 to -6. The suit was brought by plaintiffs who claim to be the infant’s next-of-kin by virtue of a judgment of adoption obtained after the infant’s death. The Court holds that defendant lacks standing to challenge the posthumous judgment of adoption. I agree with the disposition of this ease, but write to emphasize that the majority opinion should not be interpreted to deny defendants in wrongful death suits the standing to challenge plaintiffs’ status as next-of-kin. An analysis permitting defendant the right to challenge plaintiffs’ status as next-of-kin, however, would not in the circumstances of this case lead to the conclusion that this defendant may collaterally attack the judgment of adoption at issue here.
*344The Wrongful Death Act contains two provisions regarding potential plaintiffs. The first provides that either an administrator ad prosequendum of the decedent or an executor, if the decedent dies testate, is entitled to sue for the wrongful death of the decedent. N.J.S.A. 2A:31-2. The second provides that only those persons “entitled to take any intestate personal property of the decedent” may recover damages as a result of wrongful death proceedings. N.J.S.A. 2A:31-4. That portion of the statute incorporates the law of intestate succession by implication. Under that body of law, the heirs of the decedent are entitled to take his or her personal property. N.J.S.A. 3B:5-2. Judgments of adoption create such an entitlement. N.J.S.A. 2A:22-3; N.J.S.A. 3B:5-9.
Because the threshold focus in a case such as this must be on the Wrongful Death Act and whether plaintiffs are next-of-kin under that Act, it is necessary to distinguish between a defendant’s standing by way of defense to challenge a plaintiffs entitlement to bring suit and a defendant’s right to collaterally attack a final judgment. Standing is frequently expressed in terms of the plaintiffs interests. Standing generally refers to the plaintiffs entitlement to bring and maintain a suit, which rests on the party’s stake in the outcome of the litigation and an adversarial interest against opposing parties sufficient to assure an adversary proceeding. New Jersey Chamber of Commerce v. New Jersey Election Law Enforcement Comm’n, 82 N.J. 57, 67, 411 A.2d 168 (1980). The principles of standing similarly define the capacity of a defendant to raise and maintain defenses. Williams v. Bell Tel. Lab., 132 N.J. 109, 119, 623 A.2d 234 (1993). The court may not consider the merits of a case where the litigant lacks standing. Watkins v. Resorts Int’l Hotel & Casino, 124 N.J. 398, 424, 591 A.2d 592 (1991).
In this case, it is the putative status of plaintiffs as the heirs or next-of-kin of the deceased infant that entitles them to sue defendant for pecuniary loss attributable to the death of their child. It is beyond question that this defendant, being sued for malpractice under the Wrongful Death Act, has the requisite interest in the *345outcome of this case and the necessary adverseness against plaintiffs to challenge their status as next-of-kin. The fact that Dr. Zedie would not have had standing to interfere in the adoption proceeding because at the time she was a stranger to the proceeding cannot bar her from challenging the parents’ right to bring suit against her.
It is well settled that a defendant may challenge the basis for a plaintiffs claim to the status of next-of-kin and entitlement to recover under the Wrongful Death Act. See, e.g., Gangemi v. National Health Lab., 291 N.J.Super. 569, 677 A.2d 1163 (App.Div.1996) (recognizing defendant’s right to defend against sister’s wrongful death claim that she was next-of-kin and could recover pecuniary loss from decedent’s death); Sykes v. Propane Power Corp., 224 N.J.Super. 686, 541 A.2d 271 (App.Div.1988) (ruling that unmarried cohabitant of decedent could not recover damages under Wrongful Death Act); cf. De Santo v. Bobino, 168 N.J.Super. 582, 403 A.2d 959 (App.Div.1979) (ruling that grown son could not recover as dependent, but could recover as next-of-kin under Wrongful Death Act).
There are numerous examples in related contexts that confirm the right of defendants to challenge plaintiffs’ claims that they are either dependents or next-of-kin when that is a material element of their cause of action. New Jersey courts, especially in the intestacy context, recognize challenges to next-of-kin determinations. See, e.g., In re Estate of Rozet, 207 N.J.Super. 321, 504 A.2d 145 (Law Div.1985) (allowing father who abandoned his child to inherit his share of child’s intestate estate); Commercial Trust Co. of N.J. v. Adelung, 136 N.J.Eq. 37, 45, 40 A.2d 214 (Ch.1944) (recognizing minor child adopted several years after execution of trust indenture as “next-of-kin” allowing defendant to challenge adoption of adult son wishing to inherit through intestate succession because New Jersey law at that time did not permit adult adoption), aff'd, 137 N.J. Eq. 541, 45 A.2d 841 (Err. & App.1946); Hendershot v. Hendershot, 135 N.J.Eq. 232, 238, 37 A.2d 770 (Ch.1944) (allowing defendant to challenge oral agreement to *346adopt, which was never executed, after adoptive parent’s death in order to provide child with inheritance, and enforcing that agreement). Analogously, in the workers compensation context, New Jersey courts allow defendant employers to challenge the petitioner’s right to compensation, where there is some question as to whether petitioner is a dependent of the decedent or where petitioner’s legal status is otherwise in question. Stellmah v. Hunterdon Coop. G.L.F. Serv., Inc., 47 N.J. 163, 219 A.2d 616 (1966) (allowing employer to contest standing of adoptive child, and deciding on merits that employer must pay workers’ compensation to child as dependent); see Parkinson v. J. & S. Tool, 64 N.J. 159, 313 A.2d 609 (1974) (permitting employer’s challenge to spouse’s right to bring workers’ compensation claim, and holding that de facto spouse is entitled to dependency benefits under workers’ compensation statute).
The Court identifies the basic issue as “whether Dr. Zedie has standing to move to vacate the final judgment of adoption.” Ante at 348, 734 A.2d at 313. It concludes that Dr. Zedie, not being a natural parent, guardian, or care-provider of the child, would not have been entitled to notice of the adoption complaint and hearings and would not have had “the right to object” to the adoption. Ibid, (quoting R.K. v. A.J.B., 284 N.J.Super. 687, 692, 666 A.2d 215 (Ch.Div.1995)). The question to be addressed, however, is whether plaintiffs are Baby T’s next-of-kin under the Wrongful Death Act. That issues poses potentially difficult questions of statutory interpretation of the Wrongful Death Act. See, e.g., Negron v. Llarena, 156 N.J. 296, 716 A.2d 1158 (1998) (construing period of limitations under Wrongful Death Act in light of common law and statutory sources to include doctrine of substantial compliance); Giardina v. Bennett, 111 N.J. 412, 545 A.2d 139 (1988) (determining in light of common law and statutory sources that term “person” under Wrongful Death Act was not intended to include still-born child). In this case, however, all parties apparently agreed that the posthumous judgment of adoption would be determinative of plaintiffs’ status as next-of-kin, and for that reason *347define the issue in the case as whether defendant has standing to challenge that judgment.
If one considers defendant’s defense as posing a challenge to the adoption judgment, it may be considered a collateral attack. Collateral attacks on previously entered judgments are generally disfavored in the law, primarily due to the notion of repose. The decision of a court to grant or deny a petition for relief “will be left undisturbed unless it results from a clear abuse of discretion.” Pressler, Current N.J. Court Rules, comment on R. 4:50-1 (1999). Although a judgment may be challenged because it is void, R. 4:50-l(d), the revocation of a final judgment of adoption generally requires “very unusual facts and circumstances.” In re Adoption of O., 88 N.J.Super. 30, 36, 210 A.2d 440 (Cty.Ct.1965). A “catchall” provision also permits a judgment to be vacated for “any other reason justifying relief from the operation of the judgment or order.” R. 4:50-l(f). This portion of the rule is intended to provide relief to litigants in exceptional situations. Court Invest. Co. v. Perillo, 48 N.J. 334, 341, 225 A.2d 352 (1966). This case, however, does not require the application of these rules.
It is the legal effect of the challenged adoption judgment that apparently will determine whether defendant can succeed in disputing plaintiffs’ status as next-of-kin. Principles of equitable estoppel, not standing, should be invoked and applied in determining whether, in these circumstances, the defendant should be entitled to set aside a judgment or neutralize its legal effect. The factors that are implicated by the doctrine of equitable estoppel include the relationship of the parties, the surrounding circumstances giving rise to the litigation, and the nature of the claims and defenses as between the parties. See, e.g., Heuer v. Heuer, 152 N.J. 226, 232-235, 704 A.2d 913 (1998) (declining to set aside an eleven-year-old marriage based on invalidity of ancient divorce under equitable doctrine of estoppel); Kazin v. Kazin, 81 N.J. 85, 98, 405 A.2d 360 (1979); cf. Newburgh v. Arrigo, 88 N.J. 529, 538-41, 443 A.2d 1031 (1982) (applying presumptive validity of last of *348two or more marriages, but declining to find wife-in-fact to be “heir”).
The application of the doctrine of equitable estoppel is appropriate in this case. We may assume the relationship between the parties was that of doctor-patient; the plaintiffs functioned as parents of the child; they were the persons exercising parental authority regarding the infant’s well being. When the doctor undertook treatment of the child, she looked to and relied on plaintiffs as the infant’s parents to provide informed consent, to authorize medical treatment, and to be responsible for payment for her professional services. We may further assume defendant considered herself to be fully responsible and accountable to plaintiffs for the medical treatment to be rendered, and for the ensuing results. Also, that defendant voluntarily undertook to perform those professional services based on the strength of the parental relationship and authority. In the malpractice action itself those facts would be germane. The judgment of adoption was in no way relevant in the congeries of facts giving rise to the relationship among the parties and their respective rights and duties. It was only after the critical events transpired, and not until after the commencement of this malpractice suit, that the doctor began to question the validity of the plaintiffs’ status as parents. Because defendant had not contested plaintiffs’ parental role before, it would be unfair to plaintiffs to allow defendant to challenge their parental role now. Further, as noted by the majority and Judge Shebell in his dissent below, Dr. Zedie will not be prejudiced if she is precluded from challenging the legal effect of the judgment of adoption because she still has the opportunity to confront the merits and present a complete defense in the malpractice action. 311 N.J.Super. 408, 417-18, 709 A.2d 1381 (1998).
The application of equitable estoppel calls for a close and focused analysis of the interests of the parties and the circumstances giving rise to the claims and defenses, a weighing of the equities. It is the analysis that should be followed in determining *349whether such a reposed judgment, otherwise remote from the current action, should be set aside and its legal effect negated. No equitable reasons present themselves that would require a court to reopen the judgment of adoption. As the Court pointed out in Heuer, supra, “[pjrinciples of equity must be applied in light of the totality of the circumstances.” 152 N.J. at 235, 704 A2d 913. I would find that principles of equity as applied to the facts in this case estop defendant from collaterally challenging the legal effect of the posthumous judgment of adoption of Baby T. That defendant is estopped from bringing such a challenge does not result in an injustice to her, and avoids an outcome that would be unfair to plaintiffs.
Therefore, I agree with the Court’s reversal of the Appellate Division’s judgment.