with whom The Chief Justice joins, dissenting.
Only two Terms ago, when reviewing an aspect of the Secretary’s methodology for evaluating disability applications *542under this Act, we emphasized that “Congress has ‘conferred on the Secretary exceptionally broad authority’ ” in this context, and we stated that the Secretary’s regulations were therefore entitled to great deference. Bowen v. Yuckert, 482 U. S. 137, 145 (1987), quoting Heckler v. Campbell, 461 U. S. 458, 466 (1983). Because the majority has failed to abide by this principle, I respectfully dissent.
As this case involves a challenge to an agency’s interpretation of a statute that the agency was entrusted to administer, Chevron U. S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U. S. 837 (1984), provides the framework for our review. We should therefore first ask whether Congress has expressed a clear intent on the question at issue here; if so, we should enforce that intent. If not, as I think is the case, we should defer to the agency’s interpretation as long as it is permissible. Id., at 842-845.
Section 1614(a)(3)(A) of the Social Security Act, 42 U. S. C. § 1382c(a)(3)(A) (1982 ed.), provides that a person is disabled if he is unable by reason of any medically determinable physical or mental impairment to engage in any substantial gainful employment; subsection (3)(B) further defines “disability” by providing that the impairment or impairments must be severe enough, considering the person’s age, education, and work experience, to prevent him from engaging in any kind of substantial gainful employment which exists in the national economy. The Secretary has implemented the statute with respect to adults by regulations listing certain impairments that he will, without more, consider disabling because each of them would prevent an adult from engaging in any kind of gainful employment. 20 CFR pt. 404, subpt. P, App. 1 (1989). If not suffering from one of those impairments or its equivalent, an adult is then given further consideration as required by subsection (a)(3)(B) in order to determine whether in light of his impairment and the specified nonmedical factors he could perform any substantial gainful activities in the national labor market.
*543At the end of 42 U. S. C. § 1382c(a)(3)(A) (1982 ed.), with its definition of disability, is a parenthetical provision defining that term in the case of persons under 18: “or, in the case of a child under the age of 18, if he suffers from any medically determinable physical or mental impairment of comparable severity.” There is no reference to nonmedical factors in this definition and no references to specific consequences that an impairment must or should produce. Furthermore, neither “comparable,” “severity,” nor the two words together are there or elsewhere defined in the Act, and their meaning is anything but clear. The severity of an impairment that disables an adult is measured by its effects on the ability to engage in gainful employment. But that yardstick is not useful with respect to children, whose inability to work is not due to mental or physical impairment, but to the stage of their development and the labor market. Given this task of comparing apples and oranges, it is understandable that the Secretary implemented the statute with respect to children in a somewhat different manner than he did for adults, and surely there is no direction in the statute to employ the same methodology for both groups.
Under the regulations applying to children, a person under 18 will be considered disabled if suffering from a Part A impairment listed for adults or its equivalent, as long as the disease’s processes have a similar effect on adults and younger persons. Because vocational considerations are largely beside the point in dealing with children — a fact that the Secretary submits Congress recognized in referring only to medical considerations in subsection (a)(3)(A)’s definition of what would disable a child — the regulations do not provide for further consideration of the child in light of such factors. Instead, a child not suffering from a Part A impairment is evaluated under an additional listing of impairments in Part B of Appendix 1 to subpart P, any of which, or its equivalent, will be deemed sufficient to disable a child. The preamble to Part B, published in 1977, 42 Fed. Reg. 14705, stated that in *544identifying medical criteria that would establish disability for a child, the Secretary had placed primary emphasis on the effects of physical and mental impairments in children, and the restrictions on growth, learning, and development imposed on the child by the impairments. The impairments that were determined to affect the child’s development to the same extent that the adult criteria have on an adult’s ability to engage in substantial gainful activity were deemed to be of “comparable severity” to the disabling adult impairments.
I do not find this approach to be an impermissible implementation of the rather ambiguous congressional directives with respect to children. Surely it cannot be said that the regulations, insofar as they use the Part A and Part B listings, singly or in combination, to identify disability in children, are inconsistent with the statute and void on their face. And as I understand it, no one claims that they are. What is submitted is, first, that the listings do not identify all of the specific medical impairments that should be considered disabling, and second, that each child not deemed disabled under Parts A and B must be evaluated in terms of both his or her medical impairments and nonmedical factors, as are adults.
These alleged deficiencies are said to be sufficient to invalidate the regulations on their face. But surely these claims, if true, only would demonstrate that the regulations do not go far enough. Furthermore, the claims purport to be supported by descriptions of various unlisted impairments and anecdotal evidence, none of which, it seems to me, has been adjudged by a court to be sufficient to demonstrate that the Part B impairments, or their equivalents, fail to identify impairments that will have comparably severe effects on a child’s development as the disabling impairments for an adult will have on an adult’s ability to engage in substantial gainful employment. If there are medically determinable diseases or impairments that should be considered disabling because of comparable severity to those affecting adults, the children *545suffering from them should claim disability, make their case before the Secretary, and take the case to court if their claims are rejected.1 As for the more general attack on the regulation — that they do not provide for individualized evaluation based on nonmedical factors —the Secretary contends that it is a reasonable construction of section 3(A) to confine disabling criteria to medical factors where children are concerned. In any event, rather than declaring the regulations wholly or partly void on their face, the Court would be better advised to insist on children making out their claims in individual cases; only then can a court confidently say that the medically identifiable impairment, though neither a listed impairment nor its equivalent, is nevertheless of “comparable severity” and hence disabling when considered with nonmedical factors.
I thus largely agree with District Judge Fullam’s view of this case:
“Plaintiff’s argument may well be valid, in many cases; but errors in applying the regulations in some cases do not demonstrate invalidity of the regulations themselves. Part B of the Secretary’s listings of impairments, 20 CFR §416.925, is not facially invalid or incom-*546píete, seems to provide the necessary flexibility, and, in my view, permits the award of benefits in conformity with the intent of Congress. If these criteria are being misapplied or misinterpreted, the remedy lies in the appeal process in individual cases, not in a class-action decree.” Zebley v. Heckler, 642 F. Supp. 220, 222 (ED Pa. 1986).
The difference, furthermore, between the Secretary’s regulatory approach toward adults and his approach toward children accords with the different purposes underlying the disability programs for the two groups. Congress provided disability benefits for adults in order to ensure “the basic means of replacing earnings that have been lost as a result of . . . disability” for those who “are not able to support themselves through work . . . .” H. R. Rep. No. 92-231, pp. 146-147 (1971). For this reason, insofar as adults are concerned, the Act defines disabilities in terms of the effect that the disabilities have on the claimant’s ability to function in the workplace. In light of this purpose, it is appropriate for the Secretary to evaluate adults not only in terms of the severity of their impairment, but also in terms of their residual functional capacity to perform work.
By contrast, Congress had a different set of considerations in mind when it provided for children’s benefits. Recognizing that disabled children from low-income households are “among the most disadvantaged of all Americans,” Congress provided special disability benefits for these persons “because their needs are often greater than those of nondisabled children.” H. R. Rep. No. 92-231, supra, at 147-148. In other words, Congress’ aim in providing benefits to these individuals was not to replace lost income, but rather to provide for their special health care expenses, such as the home health care costs arising out of the child’s medical disability. It is consistent with this quite distinct púrpose to focus consideration on the severity of the child’s impairment from a medical perspective alone, without individualized consider*547ation of vocational or similar factors or the claimant’s residual functional capacity. The nature and severity of a child’s impairment, rather than the child’s ability to contribute to his family’s income, will necessarily determine the child’s entitlement to benefits.2
I also note that the majority faults the regulations on the grounds that they do not adequately provide for considering multiple impairments together. Ante, at 534. As 42 U. S. C. § 1382c(a)(3)(F) (1982 ed., Supp. IV) requires, however, the regulations expressly provide that impairments in combination may add up to qualify for benefits. 20 CFR §416.923 (1989). The Court of Appeals recognized that the Secretary’s regulations faithfully implement the statutory mandate “by providing generally that the combined effect of all of a claimant’s impairments will be considered throughout the disability determination process.” Zebley v. Bowen, 855 F. 2d 67, 76 (CA3 1988). There is no cross-petition challenging this aspect of the judgment below, and the Court should therefore not expand the relief obtained in the Court of Appeals.
In sum, because I cannot conclude that the Secretary’s method for evaluating child-disability claims is an impermis*548sible construction of the Act, I dissent. The Social Security Administration processes over 100,000 child-disability claims a year. The agency has a finite amount of funds with which to work. By requiring the Secretary to conduct unspecified individualized determinations in cases where an applicant fails to satisfy the agency that he is otherwise disabled, the majority imposes costs on the agency that surely will detract from the pool of benefits available to the unfortunate children that Congress has sought to protect through the Supplemental Security Income Program.
The majority suggests that the agency has conceded that its listing approach is not intended to satisfy the statutory standard of “comparable severity” because the Secretary only designed the lists to compensate claimants who suffer from disabilities that prevent any gainful activity, rather than claimants who suffer from disabilities that prevent any substantial gainful activity. It is difficult, however, particularly in light of the agency’s interpretation of its own regulations, to extract from them an admission on the agency’s part that it has failed to fulfill its statutory responsibilities. The regulations specifically state both that “[t]he law defines disability as the inability to do any substantial gainful activity by reason of any medically determinable physical or mental impairment ...” and that “[i]f you are under age 18, we will consider you disabled if you are suffering from any medically determinable physical or mental impairment which compares in severity to an impairment that would make an adult (a person over 18) disabled.” 20 CFR §§416.905, 416.906 (1989).
Congress’ acquiescence in the Secretary’s regulatory technique for assessing child-disability applications supports the position that the Secretary’s approach is reasonable. In 1976, Congress directed the Secretary to publish his criteria for evaluating disability payments for children. Unemployment Compensation Amendments of 1976, § 501(b), 90 Stat. 2685. Despite the majority’s contention to the contrary, the history of this legislation indicates that Congress understood and, at least implicitly, condoned the Secretary’s methodology for evaluating child-disability claims. The Senate Report states:
“The regulations which have been issued with regard to disability for children state that if a child’s impairments are not those listed, eligibility may still be met if the impairments ‘singly or in combination . . . are determined by the Social Security Administration, with appropriate consideration of the particular effect of the disease processes in childhood, to be medically the equivalent of a listed impairment.’” S. Rep. No. 94-1265, p. 24 (1976).