The National Gay Task Force (NGTF), whose membership includes teachers in the Oklahoma public school system, filed this action in the district court challenging the facial constitutional validity of Okla.Stat. tit. 70, § 6-103.15. The district court held that the statute was constitutionally valid. On appeal NGTF contends that the statute violates plaintiff’s members’ rights to privacy and equal protection, that it is void for vagueness, that it violates the Establishment Clause, and, finally, that it is over-broad.
The challenged statute, Okla.Stat. tit. 70, § 6-103.15, provides:
“A. As used in this section:
1. ‘Public homosexual activity’ means the commission of an act defined in Section 886 of Title 21 of the Oklahoma Statutes, if such act is:
a. committed with a person of the same sex, and
b. indiscreet and not practiced in private;
2. ‘Public homosexual conduct’ means advocating, soliciting, imposing, encouraging or promoting public or private homosexual activity in a manner that creates a substantial risk that such conduct will come to the attention of school children or school employees; and
3. ‘Teacher’ means a person as defined in Section 1-116 of Title 70 of the Oklahoma Statutes.
B. In addition to any ground set forth in Section 6-103 of Title 70 of the Oklahoma Statutes, a teacher, student teacher or a teachers’ aide may be refused employment, or reemployment, dismissed, or suspended after a finding that the teacher or teachers’ aide has:
1. Engaged in public homosexual conduct or activity; and
2. Has been rendered unfit, because of such conduct or activity, to hold a position as a teacher, student teacher or teachers’ aide.
C. The following factors shall be considered in making the determination whether the teacher, student teacher or teachers’ aide has been rendered unfit for his position:
1. The likelihood that the activity or conduct may adversely affect students or school employees;
2. The proximity in time or place the activity or conduct to the teacher’s, student teacher’s or teachers’ aide’s official duties;
3. Any extenuating or aggravating circumstances; and
4. Whether the conduct or activity is of a repeated or continuing nature which tends to encourage or dispose school children toward similar conduct or activity.”
The trial court held that the statute reaches protected speech but upheld the constitutionality of the statute by reading a “material and substantial disruption” test into it. We disagree. The statute proscribes protected speech and is thus facially overbroad, and we cannot read into the statute a “material and substantial disrup*1273tion” test. Therefore, we reverse the judgment of the trial court.
I
We see no constitutional problem in the statute’s permitting a teacher to be fired for engaging in “public homosexual activity.” Section 6-103.15 defines “public homosexual activity” as the commission of an act defined in Okla.Stat. tit. 21, § 886, that is committed with a person of the same sex and is indiscreet and not practiced in private. In support of their argument that this provision violates their members’ right of privacy, plaintiff cites Baker v. Wade, 553 F.Supp. 1121 (N.D.Tex.1982), and New York v. Onofre, 51 N.Y.2d 476, 434 N.Y.S.2d 947, 415 N.E.2d 936 (1980), cert. denied, 451 U.S. 987, 101 S.Ct. 2323, 68 L.Ed.2d 845 (1981). Both of those cases held that the constitution protects consensual, noncommercial sexual acts in private between adults. Baker and Onofre are inapplicable to the instant case. Section 6-103.15 does not punish acts performed in private. Thus, the right of privacy, whatever its scope in regard to homosexual acts, is not implicated. See Lovisi v. Slayton, 539 F.2d 349 (4th Cir.), cert. denied, 429 U.S. 977, 97 S.Ct. 485, 50 L.Ed.2d 585 (1976).
The trial court correctly rejected plaintiff’s contention that the Oklahoma statute is vague in regard to “public homosexual activity.” In Village of Hoffman Estates v. The Flipside, Hoffman Estates, Inc., 455 U.S. 489, 102 S.Ct. 1186, 71 L.Ed.2d 362 (1982), the Court outlined the doctrines of facial overbreadth and vagueness. Regarding vagueness the Court said:
“A law that does not reach constitutionally protected conduct and therefore satisfies the overbreadth test may nevertheless be challenged on its face as unduly vague, in violation of due process. To succeed, however, the complainant must demonstrate that the law is impermissibly vague in all of its applications.”
455 U.S. at 497, 102 S.Ct. at 1193. Plaintiff makes no such showing. The Oklahoma cases construing the “crime against nature” statute have clearly defined the acts that the statute proscribes.1
Plaintiff also argues that the statute violates its members’ right to equal protection of the law. We cannot find that a classification based on the choice of sexual partners is suspect, especially since only four members of the Supreme Court have viewed gender as a suspect classification. Frontiero v. Richardson, 411 U.S. 677, 93 S.Ct. 1764, 36 L.Ed.2d 583 (1973). See also Baker v. Wade, 553 F.Supp. 1121, 1144 n. 58. Thus something less than a strict scrutiny test should be applied here. Surely a school may fire a teacher for engaging in an indiscreet public act of oral or anal intercourse. See Amback v. Norwick, 441 U.S. 68, 80, 99 S.Ct. 1589, 1596, 60 L.Ed.2d 49 (1979). We also agree that the district court correctly rejected the Establishment Clause claim. See Harris v. McCrae, 448 U.S. 297, 100 S.Ct. 2671, 65 L.Ed.2d 784 (1980).
II
The part of § 6-103.15 that allows punishment of teachers for “public homosexual conduct” does present constitutional problems. To be sure, this is a *1274facial challenge, and facial challenges based on First Amendment overbreadth are “strong medicine” and should be used “sparingly and only as a last resort.” Broadrick v. Oklahoma, 413 U.S. 601, 613, 93 S.Ct. 2908, 2916, 37 L.Ed.2d 830 (1973). Nonetheless, invalidation is an appropriate remedy in the instant case because this portion of § 6-103.15 is overbroad, is “not readily subject to a narrowing construction by the state courts,” and “its deterrent effect on legitimate expression is both real and substantial.” Erznoznik v. City of Jacksonville, 422 U.S. 205, 216, 95 S.Ct. 2268, 2276, 45 L.Ed.2d 125 (1975). Also, we must be especially willing to invalidate a statute for facial overbreadth when, as here, the statute regulates “pure speech.” New York v. Ferber, 458 U.S. 747, 772-773, 102 S.Ct. 3348, 3362-3363, 70 L.Ed.2d 587 (U.S.1982); Broadrick, 413 U.S. at 615, 93 S.Ct. at 2917.
Section 6-103.15 allows punishment of teachers for “public homosexual conduct,” which is defined as “advocating, soliciting, imposing, encouraging or promoting public or private homosexual activity in a manner that creates a substantial risk that such conduct will come to the attention of school children or school employees.” Okla.Stat. tit. 70, § 6-103.-15(A)(2). The First Amendment protects “advocacy” even of illegal conduct except when “advocacy” is “directed to inciting or producing imminent lawless action and is likely to incite or produce such action.” Brandenburg v. Ohio, 395 U.S. 444, 447, 89 S.Ct. 1827, 1829, 23 L.Ed.2d 430 (1969). The First Amendment does not permit someone to be punished for advocating illegal conduct at some indefinite future time. Hess v. Indiana, 414 U.S. 105, 109, 94 S.Ct. 326, 329, 38 L.Ed.2d 303 (1973).
“Encouraging” and “promoting,” like “advocating,” do not necessarily imply incitement to imminent action. A teacher who went before the Oklahoma legislature or appeared on television to urge the repeal of the Oklahoma anti-sodomy statute would be “advocating,” “promoting,” and “encouraging” homosexual sodomy and creating a substantial risk that his or her speech would come to the attention of school children or school employees if he or she said, “I think it is psychologically damaging for people with homosexual desires to suppress those desires. They should act on those desires and should be legally free to do so.” Such statements, which are aimed at legal and social change, are at the core of First Amendment protections. As in Erznoznik, the statute by its plain terms is not easily susceptible of a narrowing construction. The Oklahoma legislature chose the word “advocacy” despite the Supreme Court’s interpretation of that word in Brandenburg. Finally, the deterrent effect of § 6-103.15 is both real and substantial. It applies to all teachers, substitute teachers, and teachers aides in Oklahoma. To protect their jobs they must restrict their expression. See Erznoznik, 422 U.S. at 217, 95 S.Ct. at 2276. Thus, the § 6-103.15 proscription of advocating, encouraging, or promoting homosexual activity is unconstitutionally overbroad.
We recognize that a state has interests in regulating the speech of teachers that differ from its interests in regulating the speech of the general citizenry. Pickering v. Board of Education, 391 U.S. 563, 568, 88 S.Ct. 1731, 1734, 20 L.Ed.2d 811 (1968). But a state’s interests outweigh a teacher’s interests only when the expression results in a material or substantial interference or disruption in the normal activities of the school. See Tinker v. Des Moines Independent Community School District, 393 U.S. 503, 89 S.Ct. 733, 21 L.Ed.2d 731 (1969). This Court has held that a teacher’s First Amendment rights may be restricted only if “the employer shows that some restriction is necessary to prevent the disruption of official functions or to insure effective performance by the employee.” Childers v. Independent School District No. 1, 676 F.2d 1338, 1341 (10th Cir.1982). Defendant has made no such showing.
The statute declares that a teacher may be fired under § 6-103.15 only if there is a finding of “unfitness” and lists *1275factors that are to be considered in determining “unfitness”: whether the activity or conduct is likely to adversely affect students or school employees; whether the activity or conduct is close in time or place to the teacher’s, student teacher’s or teachers aide’s official duties; whether any extenuating or aggravating circumstances exist; and whether the conduct or activity is of a repeated or continuing nature which tends to encourage or dispose school children toward similar conduct or activity. An adverse effect on students or other employees is the only factor among those listed in § 6-103.15 that is even related to a material and substantial disruption. And although a material and substantial disruption is an adverse effect, many adverse effects are not material and substantial disruptions. The statute does not require that the teacher’s public utterance occur in the classroom. Any public statement that would come to the attention of school children, their parents, or school employees that might lead someone to object to the teacher’s social and political views would seem to justify a finding that the statement “may adversely affect” students or school employees. The statute does not specify the weight to be given to any of the factors listed. An adverse effect is apparently not even a prerequisite to a finding of unfitness. A statute is saved from a challenge to its overbreadth only if it is “readily subject” to a narrowing construction. It is not within this Court’s power to construe and narrow state statutes. Grayned v. City of Rockford, 408 U.S. 104, 110, 92 S.Ct. 2294, 2299, 33 L.Ed.2d 222 (1972). The unfitness requirement does not save § 6-103.15 from its unconstitutional over-breadth.
Ill
The parts of § 6-103.15 that deal with “public homosexual conduct” can be severed from the rest of the statute without creating a result that the legislature did not intend or contemplate. See Tulsa Exposition and Fair Corp. v. Board of County Commissioners, 468 P.2d 501, 507 (Okl.1970); see also Hejira Corp. v. MacFarlane, 660 F.2d 1356, 1362-63 (10th Cir.1981). We reverse the judgment of the district court, holding that the statute, insofar as it punishes “homosexual conduct,” as that phrase is defined in the statute to include “advocating ... encouraging or promoting public or private homosexual activity” is unconstitutional. We also hold that the unconstitutional portion is severable from the part of the statute that proscribes “homosexual activity,” and we find that portion constitutional.
REVERSED.
. Section 886 provides: "Every person who is guilty of the detestable and abominable crime against nature, committed with mankind or with a beast, is punishable by imprisonment in the penitentiary not exceeding ten (10) years.” The Oklahoma Court of Criminal Appeals has held that § 886 proscribes oral and anal copulation. Berryman v. State, 283 P.2d 558, 563 (Okl.Cr.App.1955). In Wainwright v. Stone, 414 U.S. 21, 94 S.Ct. 190, 38 L.Ed.2d 179 (1973), the Court held that an almost identical Florida statute was not unconstitutionally vague because the Florida courts had specified that the statute applied to oral and anal copulation.
"When a state statute has been construed to forbid identifiable conduct so that ‘interpretation by [the state court] puts these words in the statute as definitely as if it had been so amended by the legislature,’ claims of impermissible vagueness must be judged in that light."
414 U.S. at 23, 94 S.Ct. at 192, citing Winters v. New York, 333 U.S. 507, 514, 68 S.Ct. 665, 666, 92 L.Ed. 840 (1948).