opinion: Justice Marshall
  delivered the opinion of the Court.
  The question presented is whether Title VII of the Civil Rights Act of 1964, as amended by the Pregnancy Discrimination Act of 1978, pre-empts a state statute that requires employers to provide leave and reinstatement to employees disabled by pregnancy.
  HH
  California s Fair Employment and Housing Act (FEHA), Cal. Gov’t Code Ann. § 12900 et seq. (West 1980 and Supp. 1986), is a comprehensive statute that prohibits discrimination in employment and housing. In September 1978, California amended the FEHA to proscribe certain forms of employment discrimination on the basis of pregnancy. See Cal. Labor Code Ann. §1420.35, 1978 Cal. Stats., ch. 1321, §1, pp. 4320-4322 (West Supp. 1979), now codified at Cal. Gov’t Code Ann. § 12945(b)(2) (West 1980). Subdivision (b)(2) — the provision at issue here — is the only portion of the statute that applies to employers subject to Title VII. See § 12945(e). It requires these employers to provide female employees an unpaid pregnancy disability leave of up to four months. Respondent Fair Employment and Housing Commission, the state agency authorized to interpret the FEHA, has construed § 12945(b)(2) to require California employers to reinstate an employee returning from such pregnancy leave to the job she previously held, unless it is no longer available due to business necessity. In the latter case, the employer must make a reasonable, good-faith effort to place the employee in a substantially similar job. The statute does not compel employers to provide paid leave to pregnant employees. Accordingly, the only benefit pregnant workers actually derive from § 12945(b)(2) is a qualified right to reinstatement.
  Title VII of the Civil Rights Act of 1964, 42 U. S. C. §2000e et seq., also prohibits various forms of employment discrimination, including discrimination on the basis of sex. However, in General Electric Co. v. Gilbert, 429 U. S. 125 (1976), this Court ruled that discrimination on the basis of pregnancy was not sex discrimination under Title VII. In response to the Gilbert decision, Congress passed the Pregnancy Discrimination Act of 1978 (PDA), 42 U. S. C. §2000e(k). The PDA specifies that sex discrimination includes discrimination on the basis of pregnancy.
  rH l-H
  Petitioner California Federal Savings & Loan Association (Cal Fed) is a federally chartered savings and loan association based in Los A.ngeles; it is an employer covered by both Title VII and §l2IÍ45(b)(2)^ Cal Fed has a facially neutral leave policy that permits" employees who have completed three months of service to take unpaid leaves of absence for a variety of reasons, including disability and pregnancy. Although it is Cal Fed’s policy to try to provide an employee taking unpaid leave with a similar position upon returning, Cal Fed expressly reserves the right to terminate an employee who has taken a leave of absence if a similar position is not available.
  Lillian Garland was employed by Cal Fed as a receptionist for several years. In January 1982, she took a pregnancy disability leave. When she was able to return to work in April of that year, Garland notified Cal Fed, but was informed that her job had been filled and that there were no receptionist or similar positions available. Garland filed a complaint with respondent Department of Fair Employment and Housing, which issued an administrative accusation against Cal Fed on her behalf.' Respondent" charged Cal Fed with violating § 12945(b)(2) of the FEHA.' 'Prior to .the scheduled hearing before respondent Fair Employment and Housing Commission, Cal Fed, joined by petitioners Merchants and Manufacturers Association and the California Chamber of Commerce, brought this action in the United States District Court for the Central District of California. They sought a declaration that § 12945(b)(2) is inconsistent with and pre-empted by Title VII and an injunction against enforcement of the section. The District Court granted petitioners’ motion for summary judgment. 33 EPD ¶ 34,227, p. 32781, 34 FEP Cases 562 (1984). Citing Newport News Shipbuilding & Dry Dock Co. v. EEOC, 462 U. S. 669 (1983), the court stated that “California employers who comply with state law are subject to reverse discrimination suits under Title VII brought by temporarily disabled males who do not receive the same treatment as female employees disabled by pregnancy . . . .” 34 FEP Cases, at 568. On this basis, the District Court held that “California state law and the policies of interpretation and enforcement. . . which require preferential treatment of female employees disabled by pregnancy, childbirth, or related medical conditions are pre-empted by Title VII and are null, void, invalid and inoperative under the Supremacy Clause of the United States Constitution.” Ibid.
  The United States Court of Appeals for the Ninth Circuit reversed. 758 F. 2d 390 (1985). It held that “the district court’s conclusion that section 12945(b)(2) discriminates against men on the basis of pregnancy defies common sense, misinterprets case law, and flouts Title VII and the PDA.” Id., at 393 (footnote omitted). Based on its own reading of Newport News, the Court of Appeals found that the PDA does not “demand that state law be blind to pregnancy’s existence.” 758 F. 2d, at 395. The court held that in enacting the PDA Congress intended “to construct a floor beneath which pregnancy disability benefits may not drop — not a ceiling above which they may not rise. ” Id., at 396. Because it found that the California statute furthers the goal of equal employment opportunity for women, the Court of Appeals concluded: “Title VII does not preempt a state law that guarantees pregnant women a certain number of pregnancy disability leave days, because this is neither inconsistent with, nor unlawful under, Title VII.” Ibid.
  We granted certiorari, 474 U. S. 1049 (1986), and we now affirm.
  III
  A
  In determining whether a state statute is pre-empted by federal law and therefore invalid under the Supremacy Clause of the Constitution, our sole task is to ascertain the intent of Congress. See Shaw v. Delta Air Lines, Inc., 463 U. S. 85, 95 (1983); Malone v. White Motor Corp., 435 U. S. 497, 504 (1978). Federal law may supersede state law in several different ways. First, when acting within constitutional limits, Congress is empowered to pre-empt state law by so stating in express terms. E. g., Jones v. Rath Packing Co., 430 U. S. 519, 525 (1977). Second, congressional intent to pre-empt state law in a particular area may be inferred where the scheme of federal regulation is sufficiently comprehensive to make reasonable the inference that Congress “left no room” for supplementary state regulation. Rice v. Santa Fe Elevator Corp., 331 U. S. 218, 230 (1947). Neither of these bases for pre-emption exists in this case. Congress has explicitly disclaimed any intent categorically to pre-empt state law or to “occupy the field” of employment discrimination law. See 42 U. S. C. §§2000e-7 and2000h-4.
  As a third alternative, in those areas where Congress has not completely displaced state regulation, federal law may nonetheless pre-empt state law to the extent it actually conflicts with federal law. Such a conflict occurs either because “compliance with both federal and state regulations is a physical impossibility,” Florida Lime & Avocado Growers, Inc. v. Paul, 373 U. S. 132, 142-143 (1963), or because the state law stands “as an obstacle to the accomplishment and execution of the full purposes and. objectives of Congress.” Hines v. Davidowitz, 312 U. S. 52, 67 (1941). See Michigan Canners & Freezers Assn., Inc. v. Agricultural Marketing and Bargaining Bd., 467 U. S. 461, 478 (1984); Fidelity Federal Savings & Loan Assn. v. De la Cuesta, 458 U. S. 141, 156 (1982). Nevertheless, pre-emption is not to be lightly presumed. See Maryland v. Louisiana, 451 U. S. 725, 746 (1981).
  This third basis for pre-emption is at issue in this case. In two sections of the 1964 Civil Rights Act, §§708 and 1104, Congress has indicated that state laws will be pre-empted only if they actually conflict with federal law. Section 708 of Title VII provides:
  “Nothing in this title shall be deemed to exempt or relieve any person from any liability, duty, penalty, or punishment provided by any present or future law of any State or political subdivision of a State, other than any such law which purports to require or permit the doing of any act which would be an unlawful employment practice under this title.” 78 Stat. 262, 42 U. S. C. § 2000e-7.
  Section 1104 of Title XI, applicable to all titles of the Civil Rights Act, establishes the following standard for preemption:
  “Nothing contained in any title of this Act shall be construed as indicating an intent on the part of Congress to occupy the field in which any such title operates to the exclusion of State laws on the same subject matter, nor shall any provision of this Act be construed as invalidating any provision of State law unless such provision is inconsistent with any of the purposes of this Act, or any provision thereof.” 78 Stat. 268, 42 U. S. C. §2000h-4.
  Accordingly, there is no need to infer congressional intent to pre-empt state laws from the substantive provisions of Title VII; these two sections provide a “reliable indicium of congressional intent with respect to state authority” to regulate employment practice. Malone v. White Motor Corp., supra, at 505.
  Sections 708 and 1104 severely limit Title VII’s preemptive effect. Instead of pre-empting state fair employment laws, § 708 “‘simply left them where they were before the enactment of title VIL’ ” Shaw v. Delta Air Lines, Inc., supra, at 103, n. 24 (quoting Pervel Industries, Inc. v. Connecticut Comm’n on Human Rights and Opportunities, 468 F. Supp. 490, 493 (Conn. 1978), affirmance order, 603 F. 2d 214 (CA2 1979), cert. denied, 444 U. S. 1031 (1980)). Similarly, § 1104 was intended primarily to “assert the intention of Congress to preserve existing civil rights laws.” 110 Cong. Rec. 2788 (1964) (remarks of Rep. Meader). See also H. R. Rep. No. 914, 88th Cong., 1st Sess., 59 (1963) (additional views of Rep. Meader). The narrow scope of preemption available under §§708 and 1104 reflects the importance Congress attached to state antidiscrimination laws in achieving Title VII’s goal of equal employment opportunity. See generally Shaw v. Delta Air Lines, Inc., 463 U. S., at 101-102; Kremer v. Chemical Construction Corp., 456 U. S. 461, 468-469, 472, 477 (1982); New York Gaslight Club, Inc. v. Carey, 447 U. S. 54, 63-65 (1980). The legislative history of the PDA also supports a narrow interpretation of these provisions, as does our opinion in Shaw v. Delta Air Lines, Inc., supra.
  In order to decide whether the California statute requires or permits employers to violate Title VII, as amended by the PDA, or is inconsistent with the purposes of the statute, we must determine whether the PDA prohibits the States from requiring employers to provide reinstatement to pregnant workers, regardless of their, policy for disabled workers generally.
  B
  Petitioners argue that the language of the federal statute itself unambiguously rejects California’s “special treatment” approach to pregnancy discrimination, thus rendering any resort to the legislative history unnecessary. They contend that the second clause of the PDA forbids an employer to treat pregnant employees any differently than other disabled employees. Because “Tt]he purpose of Congress is the ultimate touchstone’” of the pre-emption inquiry, Malone v. White Motor Corp., 435 U. S., at 504 (quoting Retail Clerks v. Schermerhorn, 375 U. S. 96, 103 (1963)), however, we must examine the PDA’s language against the background of its legislative history and historical context. As to the language of the PDA, “[i]t is a ‘familiar rule, that a thing may be within the letter of the statute and yet not within the statute, because not within its spirit, nor within the intention of its makers.’” Steelworkers v. Weber, 443 U. S. 193, 201 (1979) (quoting Church of the Holy Trinity v. United States, 143 U. S. 457, 459 (1892)). See Train v. Colorado Public Interest Research Group, Inc., 426 U. S. 1, 10 (1976); United States v. American Trucking Assns., Inc., 310 U. S. 534, 543-544 (1940).
  It is well established that the PDA was passed in reaction to this Court’s decision in General Electric Co. v. Gilbert, 429 U. S. 125 (1976). “When Congress amended Title VII in 1978, it unambiguously expressed its disapproval of both the holding and the reasoning of the Court in the Gilbert decision.” Newport News Shipbuilding & Dry Dock Co. v. EEOC, 462 U. S., at 678. By adding pregnancy to the definition of sex discrimination prohibited by Title VII, the first clause of the PDA reflects Congress’ disapproval of the reasoning in Gilbert. Newport News, supra, at 678-679, and n. 17 (citing legislative history). Rather than imposing a limitation on the remedial purpose of the PDA, we believe that the second clause was intended to overrule the holding in Gilbert and to illustrate how discrimination against pregnancy is to be remedied. Cf. 462 U. S., at 678, n. 14 (“The meaning of the first clause is not limited by the specific language in the second clause, which explains the application of the general principle to women employees”); see also id., at 688 (Rehnquist, J., dissenting). Accordingly, subject to certain limitations, we agree with the Court of Appeals’ conclusion that Congress intended the PDA to be “a floor beneath which pregnancy disability benefits may not drop — not a ceiling above which they may not rise.” 758 F. 2d, at 396.
  The context in which Congress considered the issue of pregnancy discrimination supports this view of the PDA. Congress had before it extensive evidence of discrimination against pregnancy, particularly in disability and health insurance programs like those challenged in Gilbert and Nashville Gas Co. v. Satty, 434 U. S. 136 (1977). The Reports, debates, and hearings make abundantly clear that Congress intended the PDA to provide relief for working women and to end discrimination against pregnant workers. In contrast to the thorough account of discrimination against pregnant workers, the legislative history is devoid of any discussion of preferential treatment of pregnancy, beyond acknowledgments of the existence of state statutes providing for such preferential treatment. See infra, at 287. Opposition to the PDA came from those concerned with the cost of including pregnancy in health and disability-benefit plans and the application of the bill to abortion, not from those who favored special accommodation of pregnancy.
  In support of their argument that the PDA prohibits employment practices that favor pregnant women, petitioners and several amici cite statements in the legislative history to the effect that the PDA does not require employers to extend any benefits to pregnant women that they do not already provide to other disabled employees. For example, the House Report explained that the proposed legislation “does not require employers to treat pregnant employees in any particular manner. . . . H. R. 6075 in no way requires the institution of any new programs where none currently exist.” We do not interpret these references to support petitioners’ construction of the statute. On the contrary, if Congress had intended to prohibit preferential treatment, it would have been the height of understatement to say only that the legislation would not require such conduct. It is hardly conceivable that Congress would have extensively discussed only its intent not to require preferential treatment if in fact it had intended to prohibit such treatment.
  We also find it significant that Congress was aware of state laws similar to California’s but apparently did not consider them inconsistent with the PDA. In the debates and Reports on the bill, Congress repeatedly acknowledged the existence of state antidiscrimination laws that prohibit sex discrimination on the basis of pregnancy. Two of the States mentioned then required employers to provide reasonable leave to pregnant workers. After citing these state laws, Congress failed to evince the requisite “clear and manifest purpose” to supersede them. See Pacific Gas & Electric Co. v. State Energy Resources Conservation and Development Comm’n, 461 U. S. 190, 206 (1983). To the contrary, both the House and Senate Reports suggest that these laws would continue to have effect under the PDA.
  Title VII, as amended by the PDA, and California’s pregnancy disability leave statute share a common goal. The purpose of Title VII is “to achieve equality of employment opportunities and remove barriers that have operated in the past to favor an identifiable group of . . . employees over other employees.” Griggs v. Duke Power Co., 401 U. S. 424, 429-430 (1971). See Hishon v. King & Spalding, 467 U. S. 69, 75, n. 7 (1984); Franks v. Bowman Transportation Co., 424 U. S. 747, 763 (1976); Alexander v. Gardner-Denver Co., 415 U. S. 36, 44 (1974); McDonnell Douglas Corp. v. Green, 411 U. S. 792, 800 (1973). Rather than limiting existing Title VII principles and objectives, the PDA extends them to cover pregnancy. As Senator Williams, a sponsor of the Act, stated: “The entire thrust. . . behind this legislation is to guarantee women the basic right to participate fully and equally in the workforce, without denying them the fundamental right to full participation in family life. ” 123 Cong. Rec. 29658 (1977).
  Section 12945(b)(2) also promotes equal employment opportunity. By requiring employers to reinstate women after a reasonable pregnancy disability leave, § 12945(b)(2) ensures that they will not lose their jobs on account of pregnancy disability. California’s approach is consistent with the dissenting opinion of Justice Brennan in General Electric Co. v. Gilbert, which Congress adopted in enacting the PDA. Referring to Lau v. Nichols, 414 U. S. 563 (1974), a Title VI decision, Justice Brennan stated:
  “[DJiscrimination is a social phenomenon encased in a social context and, therefore, unavoidably tákes its meaning from the desired end products of the relevant legislative enactment, end products that may demand due consideration of the uniqueness of the ‘disadvantaged’ individuals. A realistic understanding of conditions found in today’s labor environment warrants taking pregnancy into account in fashioning disability policies.” 429 U. S., at 159 (footnote omitted).
  By “taking pregnancy into account,” California’s pregnancy disability-leave statute allows women, as well as men, to have families without losing their jobs.
  We emphasize the limited nature of the benefits § 12945 (b)(2) provides. The statute is narrowly drawn to cover only the period of actual physical disability on account of pregnancy, childbirth, or related medical conditions. Accordingly, unlike the protective labor legislation prevalent earlier in this century, § 12945(b)(2) does not reflect archaic or stereotypical notions about pregnancy and the abilities of pregnant workers. A statute based on such stereotypical assumptions would, of course, be inconsistent with Title VIPs goal of equal employment opportunity. See, e. g., Los Angeles Dept. of Water and Power v. Manhart, 435 U. S. 702, 709 (1978); Phillips v. Martin Marietta Corp., 400 U. S. 542, 545 (1971) (Marshall, J., concurring).
  C
  Moreover, even if we agreed with petitioners’ construction of the PDA, we would nonetheless reject their argument that the California statute requires employers to violate Title VII. Section 12945(b)(2) does not prevent employers from complying with both the federal law (as petitioners construe it) and the state law. This is not a case where “compliance with both federal and state regulations is a physical impossibility,” Florida Lime & Avocado Growers, Inc. v. Paul, 373 U. S., at 142-143, or where there is an “inevitable collision between the two schemes of regulation.” Id., at 143. Section 12945(b)(2) does not compel California employers to treat pregnant workers better than other disabled employees; it merely establishes benefits that employers must, at a minimum, provide to pregnant workers. Employers are free to give comparable benefits to other disabled employees, thereby treating “women affected by pregnancy” no better than “other persons not so affected but similar in their ability or inability to work.” Indeed, at oral argument, petitioners conceded that compliance with both statutes “is theoretically possible.” Tr. of Oral Arg. 6.
  Petitioners argue that “extension” of the state statute to cover other employees would be inappropriate in the absence of a clear indication that this is what the California Legislature intended. They cite cases in which this Court has declined to rewrite underinclusive state statutes found to violate the Equal Protection Clause. See, e. g., Wengler v. Druggists Mutual Insurance Co., 446 U. S. 142, 152-153 (1980); Caban v. Mohammed, 441 U. S. 380, 392-393, n. 13 (1979). This argument is beside the point. Extension is a remedial option to be exercised by a court once a statute is found to be invalid. See, e. g., Califano v. Westcott, 443 U. S. 76, 89 (1979) (quoting Welsh v. United States, 398 U. S. 333, 361 (1970) (Harlan, J'., concurring in result)).
  IV
  Thus, petitioners’ facial challenge to § 12945(b)(2) fails. The statute is not pre-empted by Title VII, as amended by the PDA, because it is not inconsistent with the purposes of the federal statute, nor does it require the doing of an act which is unlawful under Title VII.
  The judgment of the Court of Appeals is
  Affirmed.
  Section 12945(b)(2) provides, in relevant part:
  “It shall be an unlawful employment practice unless based upon a bona fide occupational qualification:
  “(b) For any employer to refuse to allow a female employee affected by pregnancy, childbirth, or related medical conditions ....
  “(2) To take a leave on account of pregnancy for a reasonable period of time; provided, such period shall not exceed four months. . . . Reasonable period of time means that period during which the female employee is disabled on account of pregnancy, childbirth, or related medical conditions....
  “An employer may require any employee who plans to take a leave pursuant to this section to give reasonable notice of the date such leave shall commence and the estimated duration of such leave.”
  Originally, the statute was intended to reverse, as to California employers, the rule established by this Court’s decision in General Electric Co. v. Gilbert, 429 U. S. 125 (1976). At the time, California law prohibited school districts from discriminating on the basis of pregnancy, see former Cal. Labor Code Ann. § 1420.2 (1977), now codified at Cal. Gov’t Code Ann. § 12943 (West 1980). The first version of § 12945 simply imposed this requirement on all California employers with five or more employees. As a result of employer opposition, however, the measure was changed to its present form.
  Aware that legislation on this subject was pending before Congress, the state legislature added the following section:
  “In the event Congress enacts legislation amending Title VII of the Civil Rights Act of 1964 to prohibit sex discrimination on the basis of pregnancy, the provisions of this act, except paragraph (2) of subdivision (b). . . shall be inapplicable to any employer subject to such federal law . . . .” 1978 Cal. Stats., ch. 1321, §4, p. 4322.
  When Congress'passed the Pregnancy Discrimination Act of 1978, this section rendered the state law, except subdivision (b)(2), invalid as applied to all employers covered by Title VII. California subsequently adopted subdivision (e), which provides:
  “The provisions of this section, except paragraph (2) of subdivision (b), shall be inapplicable to any employer subject to Title VII of the federal Civil Rights Act of 1964.”
  See Cal. Gov’t Code Ann. §§ 12935(a)(1) and 12935(h) (West 1980). Respondent Department of Fair Employment and Housing is the state agency charged with enforcing the FEHA. See § 12930.
  The parties have stipulated that the Commission’s interpretation of § 12945(b)(2) is set forth in its proposed regulation as reproduced in App. 47. See also Matter of Accusation of Department of Fair Employment and Housing v. Travel Express, Case No. FEP 80-81 A7-0992s N18709 83-17 (Aug. 4, 1983) (precedential Commission decision construing § 12945 (b)(2)).
  In General Electric Co. v. Gilbert, the Court held that an otherwise comprehensive disability insurance plan did not violate Title VII because it failed to cover pregnancy-related disabilities. Relying on Geduldig v. Aiello, 417 U. S. 484 (1974), which upheld a similar plan against a Fourteenth Amendment equal protection challenge, the Court concluded that removing pregnancy from the list of compensable disabilities was not discrimination on the basis of sex. 429 U. S., at 133-136. The Court further held that “[a]s there is no proof that the package is in fact worth more to men than to women, it is impossible to find any gender-based discriminatory effect in this scheme . . . .” Id., at 138.
  Three Members of the Court dissented. See id., at 146 (opinion of Brennan, J., joined by Marshall, J.); id., at 160 (opinion of Stevens, J.). The dissenting Justices would have held that the employer’s disability plan discriminated on the basis of sex by giving men protection for all categories of risk but giving women only partial protection.
  In Nashville Gas Co. v. Satty, 434 U. S. 136, 143-146 (1977), the Court relied on Gilbert to uphold an employer’s sick-leave policy that excluded pregnancy.
  The PDA added subsection (k) to §701, the definitional section of Title VII. Subsection (k) provides, in relevant part:
  “The terms ‘because of sex’ or ‘on the basis of sex’ include, but are not limited to, because of or on the basis of pregnancy, childbirth, or related medical conditions; and women affected by pregnancy, childbirth, or related medical conditions shall be treated the same for all employment-related purposes, including receipt of benefits under fringe benefit programs, as other persons not so affected but similar in their ability or inability to work, and nothing in section 703(h) of this title shall be interpreted to permit otherwise.”
  The legislative history of the PDA reflects Congress’ approval of the views of the dissenters in Gilbert. See Newport News Shipbuilding & Dry Dock Co. v. EEOC, 462 U. S. 669, 678-679, and nn. 15-17 (1983) (citing legislative history).
  Cal Fed reinstated Garland in a receptionist position in November 1982, seven months after she first notified it that she was able to return to work.
  Petitioner Merchants and Manufacturers Association is a trade association that represents numerous employers throughout the State of California. Petitioner California Chamber of Commerce also represents many California businesses. Both organizations have members that are subject to both Title VII and § 12945(b)(2) and have disability-leave policies similar to Cal Fed’s.
  Petitioners’ complaint also alleged that the California disability-leave statute was pre-empted by § 514(a) of the Employee Retirement Income Security Act (ERISA), 29 U. S. C. § 1144(a). The parties stipulated that petitioners’ ERISA claim would be dismissed without prejudice. App. 9-10, nn. 1, 2.
  In Newport News, the Court evaluated a health insurance plan that provided female employees with benefits for pregnancy-related conditions to the same extent as for other medical conditions, but provided less extensive pregnancy benefits for spouses of male employees. The Court found that this limitation discriminated against male employees with respect to the compensation, terms, conditions, or privileges of their employment in violation of § 703(a)(1) of Title VII. “The 1978 Act [the PDA] makes clear that it is discriminatory to treat pregnancy-related conditions less favorably than other conditions. Thus petitioner’s plan unlawfully gives married male employees a benefit package for their dependents that is less inclusive than the dependency coverage provided to married female employees.” 462 U. S., at 684.
  After the District Court entered its judgment, Garland moved to intervene pursuant to Federal Rule of Civil Procedure 24(a)(2). The District Court denied her motion on several grounds: untimeliness, lack of a “direct and substantial” interest in the litigation, and adequate representation of her interests by defendants. Her appeal from the order denying intervention was consolidated with the appeal on the merits. In an unreported order, the Court of Appeals for the Ninth Circuit affirmed the denial of intervention; Garland did not seek review of that decision here.
  Representative Meader, one of the sponsors of the 1964 Civil Rights Act, proposed the precursor to § 1104 as an amendment to the Civil Rights Act, see 110 Cong. Rec. 2788 (1964), because he feared that § 708 and similar provisions in other titles were “wholly inadequate to preserve the validity and force of State laws aimed at discrimination.” H. R. Rep. No. 914, 88th Cong., 1st Sess., 59 (1963) (additional views of Rep. Meader). His version provided that state laws would not be pre-empted “except to the extent that there is a direct and positive conflict between such provisions so that the two cannot be reconciled or consistently stand together.” 110 Cong. Ree. 2787 (1964). The version ultimately adopted by Congress was a substitute offered by Representative Mathias without objection from Representative Meader. Id., at 2789. There is no indication that this substitution altered the basic thrust of § 1104.
  For example, where state or local law prohibits an employment practice, § 706(c) requires deferral of federal enforcement until state or local officials have an opportunity “to act under such State or local law to remedy the practice alleged.” § 2000e-5(d).
  See, e. g., S. Rep. No. 95-331, p. 3, n. 1 (1977) (state laws prohibiting discrimination on the basis of pregnancy would not be pre-empted, “[sjince title VII does not pre-empt State laws which would not require violating title VII”), Legislative History of the Pregnancy Discrimination Act of 1978, p. 40 (1980) (Committee Print prepared for the Senate Committee on Labor and Human Resources) (hereinafter Leg. Hist.); 123 Cong. Rec. 29643 (1977) (remarks of Sen. Williams) (state laws that create a “clear conflict” would be pre-empted).
  In Shaw v. Delta Air Lines, Inc., 463 U. S., at 100-104, we concluded that Title VII did not pre-empt a New York statute which proscribed discrimination on the basis of pregnancy as sex discrimination at a time when Title VII did not equate the two.
  Several commentators have construed the second clause of the PDA in this way. See, e. g., Note, Employment Equality Under The Pregnancy Discrimination Act of 1978, 94 Yale L. J. 929, 937 (1985); Note, Sexual Equality Under the Pregnancy Discrimination Act, 83 Colum. L. Rev. 690, 696, and n. 26 (1983).
  For example, a State could not mandate special treatment of pregnant workers based on stereotypes or generalizations about their needs and abilities. See infra, at 290.
  See Discrimination on the Basis of Pregnancy, 1977, Hearings on S. 995 before the Subcommittee on Labor of the Senate Committee on Human Resources, 95th Cong., 1st Sess., 31-33 (1977) (statement of Vice Chairman, Equal Employment Opportunity Commission, Ethel Bent Walsh); id., at 113-117 (statement of Wendy W. Williams); id., at 117-121 (statement of Susan Deller Ross); id., at 307-310 (statement of Bella S. Abzug). See also Legislation to Prohibit Sex Discrimination on the Basis of Pregnancy, Hearings on H. R. 5055 and H. R. 6075 before the Subcommittee on Employment Opportunities of the House Committee on Education and Labor, 95th Cong., 1st Sess. (1977).
  See, e. g., 123 Cong. Rec. 8144 (1977) (remarks of Sen. Bayh) (legislation “-will end employment discrimination against pregnant workers”); 124 Cong Rec. 21440 (1978) (remarks of Rep. Chisholm) (bill “affords some 41 percent of this Nation’s labor force some greater degree of protection and security without fear of reprisal due to to their decision to bear children”); id., at 21442 (remarks of Rep. Tsongas) (bill “would put an end to an unrealistic and unfair system that forces women to choose between family and career — clearly a function of sex bias in the law”); id., at 36818 (remarks of Sen. Javits) (the “bill represents only basic fairness for women employees”); id., at 38574 (remarks of Rep. Sarasin) (Subcommittee “learned of the many instances of discrimination against pregnant workers, as we learned of the hardships this discrimination brought to women and their families”).
  The statement of Senator Brooke, quoted in the dissent, post, at 300, merely indicates the Senator’s view that the PDA does not itself require special disability benefits for pregnant workers. It in no way supports the conclusion that Congress intended to prohibit the States from providing such benefits for pregnant workers. See n. 29, infra.
  See, e. g., S. Rep. No. 95-331, p. 9 (1977), Leg. Hist. 46 (discussing cost objections); H. R. Conf. Rep. No. 95-1786, pp. 3-4 (1978), Leg. Hist. 196-197 (application of the PDA to abortion).
  H. R. Rep. No. 95-948, p. 4 (1978), Leg. Hist. 150. See also S. Rep. No. 95-331, supra, at 4, Leg. Hist. 41; 123 Cong. Rec. 7540 (1977) (remarks of Sen. Williams); id., at 10582 (remarks of Rep. Hawkins); id., at 29387 (remarks of Sen. Javits); id., at 29664 (remarks of Sen. Brooke).
  See, e. g., id., at 29387 (remarks of Sen. Javits), Leg. Hist. 67 (“[S]ev-eral state legislatures . . . have chosen to address the problem by mandating certain types of benefits for pregnant employees”). See also S. Rep. No. 95-331, supra, at 3, Leg. Hist. 40; H. R. Rep. No. 95-948, supra, at 10-11, Leg. Hist. 156-157; 123 Cong. Rec. 29648 (1977) (list of States that require coverage for pregnancy and pregnancy-related disabilities); id., at 29662 (remarks of Sen. Williams).
  See, e. g., Conn. Gen. Stat. §31-126(g) (1977), now codified at §46a-60(a)(7) (1985); Mont. Rev. Codes § 41-2602 (Smith Supp. 1977), now codified at Mont. Code Ann. §§ 49-2-310 and 49-2-311 (1986). The Connecticut statute provided, in relevant part:
  “It shall be an unfair employment practice
  “(g) For an employer . . . (ii) to refuse to grant to [a pregnant] employee a reasonable leave of absence for disability resulting from such pregnancy. . . . (iii) Upon signifying her intent to return, such employee shall be reinstated to her original job or to an equivalent position with equivalent pay and accumulated seniority, retirement, fringe benefits and other service credits unless, in the ease of a private employer, the employer’s circumstances have so changed as to make it impossible or unreasonable to do so.” Conn. Gen. Stat. § 31-126(g) (1977).
  The Montana statute in effect in 1977 was virtually identical. Both have been recodified in current statutory compilations, but the leave and reinstatement requirements are unchanged. See also Mass. Gen. Laws § 149:105D (1985) (providing up to eight weeks maternity leave).
  The dissent suggests that the references to the Connecticut and Montana statutes should be disregarded, because Congress did not expressly state that it understood that “these statutes required anything more than equal treatment.” Post, at 301. However, we are not as willing as the dissent to impute ignorance to Congress. Where Congress has cited these statutes in the House and Senate Reports on the PDA, we think it fair to assume that it was aware of their substantive provisions.
  For example, the Senate Report states: “Since title VII does not preempt State laws which would not require violating title VII . . . , these States would continue to be able to enforce their State laws if the bill were enacted.” S. Rep. No. 95-331, supra, at 3, n. 1, Leg. Hist. 40.
  “Proponents of the bill repeatedly emphasized that the Supreme Court had erroneously interpreted congressional intent and that the amending legislation was necessary to reestablish the principles of Title VII law as they had been understood prior to the Gilbert decision.” Newport News Shipbuilding & Dry Dock Co. v. EEOC, 462 U. S., at 679.
  As authoritatively construed by respondent Commission, the provision will “insure that women affected by pregnancy, childbirth or related medical conditions have equal employment opportunities as persons not so affected.” California Fair Employment and Housing Commission’s Proposed Regulation, see App. 49.
  See generally B. Brown, A. Freedman, H. Katz, & A. Price, Women’s Rights and the Law 209-210 (1977). In the constitutional context, we have invalidated on equal protection grounds statutes designed “to exclude or ‘protect’ members of one gender because they are presumed to suffer from an inherent handicap or to be innately inferior. ” Mississippi University for Women v. Hogan, 458 U. S. 718, 725 (1982).
  Petitioners assert that even if § 12945(b)(2) does not require employers to treat pregnant employees differently from other disabled employees, it permits employers to do so because it does not specifically prohibit different treatment. Of course, since the PDA does not itself prohibit different treatment, it certainly does not require the States to do so. Moreover, if we were to interpret the term “permit” as expansively as petitioners suggest, the State would be required to incorporate every prohibition contained in Title VII into its state law, since it would otherwise be held to “permit” any employer action it did not expressly prohibit. We conclude that “permit” in § 708 must be interpreted to pre-empt only those state laws that expressly sanction a practice unlawful under Title VII; the term does not pre-empt state laws that are silent on the practice.
  Indeed, Congress and the California Legislature were each aware in general terms of the regulatory scheme adopted by the other when they enacted their legislation. California recognized that many of its provisions would be pre-empted by the PDA and, accordingly, exempted employers covered by Title VII from all portions of the statute except those guaranteeing unpaid leave and reinstatement to pregnant workers. Congress was aware that some state laws mandated certain benefits for pregnant workers, but did not indicate that they would be pre-empted by federal law. See supra, at 287-288.
  We recognize that, in cases where a state statute is otherwise invalid, the Court must look to the intent of the state legislature to determine whether to extend benefits or nullify the statute. By arguing that extension would be inappropriate in this case, however, post, at 302-303, and citing this as a basis for pre-emption, the dissent simply ignores the prerequisite of invalidity.
  Because we conclude that in enacting the PDA Congress did not intend to prohibit all favorable treatment of pregnancy, we need not decide and therefore do not address the question whether § 12945(b)(2) could be upheld as a legislative response to leave policies that have a disparate impact on pregnant workers.