[1] JUSTICE BLACKMUN delivered the opinion of the Court:

[2] This case involves a claim of a State's unconstitutional interference with the decision to terminate pregnancy. The particular object of the challenge is a Missouri statute excluding abortions that are not "medically indicated" from the purposes for which Medicaid benefits are available to needy persons. In its present posture, however, the case presents [an issue] not going to the merits of this dispute:   whether the plaintiff-appellees, as physicians who perform non-medically indicated abortions, have standing to maintain the suit, to which we answer that they do.

[3] The suit was filed in the United States District Court for the Eastern District of Missouri by two Missouri licensed physicians. Each plaintiff avers, in an affidavit filed in opposition to a motion to dismiss, that he "has provided, and anticipates providing abortions to welfare patients who are eligible for Medicaid payments." The plaintiffs further allege in their affidavits that all Medicaid applications filed in connection with abortions performed by them have been refused by the defendant, who is the responsible state official, in reliance on the challenged [statutory provision].

[4] In any event, each plaintiff states that he anticipates further refusals by the defendant to fund non-medically indicated abortions. Each avers that such refusals "deter [him] from the practice of medicine in the manner he considers to be most expertise [sic] and beneficial for said patients . . . and chill and thwart the ordinary and customary functioning of the doctor-patient relationship."

*  *  *

II

[5] Two distinct standing questions are presented. We have distinguished them in prior cases, e. g., Data Processing Service v. Camp, 397 U. S., at 152-153; Flast v. Cohen, 392 U. S. 83, 99 n. 20 (1968); Barrows v. Jackson, 346 U. S. 249, 255 (1953), and they are these: First, whether the plaintiff-respondents allege "injury in fact," that is, a sufficiently concrete interest in the outcome of their suit to make it a case or controversy subject to a federal court's Art. III jurisdiction, and, second, whether, as a prudential matter, the plaintiff-respondents are proper proponents of the particular legal rights on which they base their suit.

[6] A. The first of these questions needs little comment, for there is no doubt now that the respondent-physicians suffer concrete injury from the operation of the challenged statute. Their complaint and affidavits, described above, allege that they have performed and will continue to perform operations for which they would be reimbursed under the Medicaid program, were it not for the limitation of reimbursable abortions to those that are "medically indicated." If the physicians prevail in their suit to remove this limitation, they will benefit, for they will then receive payment for the abortions. The State (and Federal Government) will be out of pocket by the amount of the payments. The relationship between the parties is classically adverse, and there clearly exists between them a case or controversy in the constitutional sense. Simon v. Eastern Ky. Welfare Rights Org., 426 U. S. 26, 37-39 (1976); Investment Co. Institute v. Camp, 401 U. S. 617, 620-621 (1971); Data Processing Service v. Camp, 397 U. S., at 151-156.

[7] B. The question of what rights the doctors may assert in seeking to resolve that controversy is more difficult. The Court of Appeals adverted to what it perceived to be the doctor's own "constitutional rights to practice medicine." 508 F. 2d, at 1213. We have no occasion to decide whether such rights exist. Assuming that they do, the doctors, of course, can assert them. It appears, however, that the Court of Appeals also accorded the doctors standing to assert, and indeed granted them relief based partly upon, the rights of their patients. We must decide whether this assertion of jus tertii was a proper one.

[8] Federal courts must hesitate before resolving a controversy, even one within their constitutional power to resolve, on the basis of the rights of third persons not parties to the litigation. The reasons are two. First, the courts should not adjudicate such rights unnecessarily, and it may be that in fact the holders of those rights  either do not wish to assert them, or will be able to enjoy them regardless of whether the in-court litigant is successful or not. See Ashwander v. TVA, 297 U. S. 288, 345-348 (1936) (Brandeis, J., concurring) (offering the standing requirement as one means by which courts avoid unnecessary constitutional adjudications). Second, third parties themselves usually will be the best proponents of their own rights. The courts depend on effective advocacy, and therefore should prefer to construe legal rights only when the most effective advocates of those rights are before them. The holders of the rights may have a like preference, to the extent they will be bound by the courts' decisions under the doctrine of stare decisis. See, e. g., Baker v. Carr, 369 U. S. 186, 204 (1962) (standing requirement aimed at "assur[ing] that concrete adverseness which sharpens the presentation of the issues upon which the court so largely depends"); Holden v. Hardy, 169 U. S. 366, 397 (1898) (assertion of third parties' rights would come with "greater cogency" from the third parties themselves). These two considerations underlie the Court's general rule: "Ordinarily, one may not claim standing in this Court to vindicate the constitutional rights of some third party." Barrows v. Jackson, 346 U. S., at 255. See also Flast v. Cohen, 392 U. S., at 99 n. 20; McGowan v. Maryland, 366 U. S. 420, 429 (1961).

114

[9] Like any general rule, however, this one should not be applied where its underlying justifications are absent. With this in mind, the Court has looked primarily to two factual elements to determine whether the rule should apply in a particular case. The first is the relationship of the litigant to the person whose right he seeks to assert. If the enjoyment of the right is inextricably bound up with the activity the litigant wishes to pursue, the court at least can be sure that its construction of the right is not unnecessary in the sense that the right's enjoyment will be unaffected by the outcome of the suit.

[10] Furthermore, the relationship between the litigant and the third party may be such that the former is fully, or very nearly, as effective a proponent of the right as the latter. Thus in Griswold v. Connecticut, 381 U. S. 479 (1965), where two persons had been convicted of giving advice on contraception, the Court permitted the defendants, one of whom was a licensed physician, to assert the privacy rights of the married persons whom they advised. The Court pointed to the "confidential" nature of the relationship between the defendants and the married persons, and reasoned that the rights of the latter were "likely to be diluted or adversely affected" if they could not be asserted in such a case. Id., at 481. See also Eisenstadt v. Baird, 405 U. S. 438, 445-446 (1972) (stressing "advocate" relationship and "impact of the litigation on the third-party interests"); Barrows v. Jackson, 346 U. S., at 259 (owner of real estate subject to racial covenant granted standing to challenge such covenant in part because she was "the one in whose charge and keeping repose[d] the power to continue to use her property to discriminate or to discontinue such use"). A doctor-patient relationship similar to that in Griswold existed in Doe v. Bolton, where the Court also permitted physicians to assert the rights of their patients.410 U. S., at 188-189. Indeed, since that right was the right to an abortion, Doe would flatly control the instant case were it not for the fact that there the physicians were seeking protection from possible criminal prosecution.

[11] The other factual element to which the Court has looked is the ability of the third party to assert his own right. Even where the relationship is close, the reasons for requiring persons to assert their own rights will generally still apply. If there is some genuine obstacle to such assertion, however, the third party's absence from court loses its tendency to suggest that his right is not truly at stake, or truly important to him, and the party who is in court becomes by default the right's best available proponent. Thus, in NAACP v. Alabama, 357 U. S. 449 (1958), the Court held that the National Association for the Advancement of Colored People, in resisting a court order that it divulge the names of its members, could assert the First and Fourteenth Amendments rights of those members to remain anonymous. The Court reasoned that "[t]o require that [the right] be claimed by the members themselves would result in nullification of the right at the very moment of its assertion." Id., at 459. See also Eisenstadt v. Baird, 405 U. S., at 446; Barrows v. Jackson, 346 U. S., at 259.

[12] Application of these principles to the present case quickly yields its proper result. The closeness of the relationship is patent, as it was in Griswold and in Doe. A woman cannot safely secure an abortion without the aid of a physician, and an impecunious woman cannot easily secure an abortion without the physician's being paid by the State. The woman's exercise of her right to an abortion, whatever its dimension, is therefore necessarily at stake here. Moreover, the constitutionally protected abortion decision is one in which the physician is intimately involved. See Roe v. Wade, 410 U. S., at 153-156. Aside from the woman herself, therefore, the physician is uniquely qualified to litigate the constitutionality of the State's interference with, or discrimination against, that decision.

[13] As to the woman's assertion of her own rights, there are several obstacles. For one thing, she may be chilled from such assertion by a desire to protect the very privacy of her decision from the publicity of a court suit. A second obstacle is the imminent mootness, at least in the technical sense, of any individual woman's claim. Only a few months, at the most, after the maturing of the decision to undergo an abortion, her right thereto will have been irrevocably lost, assuming, as it seems fair to assume, that unless the impecunious woman can establish Medicaid eligibility she must forgo abortion. It is true that these obstacles are not insurmountable. Suit may be brought under a pseudonym, as so frequently has been done. A woman who is no longer pregnant may nonetheless retain the right to litigate the point because it is “`capable of repetition yet evading review.' “Roe v. Wade, 410 U. S., at 124-125. And it may be that a class could be assembled, whose fluid membership always included some women with live claims. But if the assertion of the right is to be "representative" to such an extent anyway, there seems little loss in terms of effective advocacy from allowing its assertion by a physician.

[14] For these reasons, we conclude that it generally is appropriate to allow a physician to assert the rights of women patients as against governmental interference with the abortion decision, and we decline to restrict our holding to that effect in Doe to its purely criminal context. In this respect, the judgment of the Court of Appeals is affirmed.

*  *  *

[15] Singleton v. Wulff focuses on two factors in determining whether a plaintiff can sue on behalf of a third party:  the closeness of the relationship between the plaintiff and the injured third party, and the likelihood that the third party can sue on its own behalf.  Consider how these factors were applied in the following cases:

[16] BARROWS v. JACKSON, 346 U.S. 249 (1953):  Barrows, a white person who had signed a racially restrictive covenant, was sued for breach of contract for allowing nonwhites to occupy the property.  As a defense, Barrows raised the rights of blacks, who were not parties to the lawsuit, to be free from discrimination. The Court allowed third party standing, permitting the white defendant to raise the interests of black persons to rent and own property in the community.  The Court stated that “it would be difficult if not impossible for the person whose rights are asserted to present their grievance before any court.”  Because black people were not parties to the covenant, they had no legal basis for participating in the breach of contract suit.  (The suit occurred before open housing laws were enacted that would have allowed African Americans to challenge the covenants as impermissible discrimination.)

[17] CRAIG v. BOREN, 429 U.S. 190 (1976):  Oklahoma law permitted women to buy 3.2 percent beer at age 18, but said that men could not do so until age 21. A bartender challenged the law on behalf of male customers between the ages of 18 and 21.  The bartender suffered economic loss from the law, thus fulfilling the injury requirement.  The Court allowed the bartender standing to assert the rights of his customers and explained that “vendors and those in like positions have been uniformly permitted to resist efforts at restricting their operations by acting as advocates for the rights of third parties who seek access to their market or function.”

[18] GILMORE v. UTAH, 429 U.S. 1012 (1976):  Gary Gilmore was sentenced to death in the state of Utah but chose not to pursue habeas corpus relief in federal court.  His mother sued for a stay of execution on his behalf. In a five-to-four decision, the Court refused to hear his mother’s claim. The Court’s per curiam opinion said that the defendeant had waived his rights by not pursuing them.

[19] Chief Justice Burger, in a concurring opinion, said that the mother should be denied standing: “When the record establishing a knowing and intelligent waiver of Gary Mark Gilmore’s right to seek appellate review is combined with the December 8 written response submitted to this Court, it is plain that the Court is without jurisdiction to entertain the “next friend” application filed by Bessie Gilmore.  This Court has jurisdiction pursuant to Art. III of the Constittion on ly over ‘cases and controversies,’ and we can issue stays only in aid of our jurisdiction. There is no dispute, presently before us, between Gary Mark Gilmore and the State of Utah, and the application of Bessie Gilmore manifestly fails to meet the statutory requirements to invoke this Court’s power to review the action of the Supreme Court of Utah. No authority to the contrary has been brought to our attention, and nothing suggested in dissent bears on the threshold question of jurisdiction.

[20] In 2004, the Court returned to the issue of third party standing in a high profile case addressing whether the words “under God” in the Pledge of Allegiance are constitutional.  The Court dismissed the case on standing grounds.  In ELK GROVE UNIFIED SCHOOL DISTRICT v. NEWDOW, 542 U.S. 1 (2004), the Court held that a father lacked standing to sue on behalf of his daughter because he lacked legal custody for the girl and the mother who had legal custody did not want to sue.  Justice Stevens wrote, “In our view, it is improper for the federal courts to entertain a claim by a plaintiff whose standing to sue is founded on family law rights that are in dispute when prosecution of the lawsuit may have an adverse effect on the person who is the source of the plaintiff’s claimed standing.  When hard questions of domestic relations are sure to affect the outcome, the prudent course is for the federal court to stay its hand rather than reach out to resolve a weighty question of federal constitutional law.  There is a vast difference between Newdow’s right to communicate with his child – which both California law and the First Amendment recognize – and his claimed right to shield his daughter from influences to which she is exposed in school despite the terms of the custody order.  We conclude that, having been deprived under California law of the right to sue as next friend, Newdow lacks prudential standing to bring this suit in federal court.” Yet, why is Newdow’s ability to sue based on who has custody of the girl?  Does he not have a claim that his own right to control the religious upbringing of his daughter is infringed by the requirement of “under God” in the Pledge of Allegiance?