KAPLAN, J.

Believing that a rule of the defendant Massachusetts Interscholastic Athletic Association, Inc., (MIAA) that "No boy may play on a girls' team," as impressed upon and carried out by public schools under school committee jurisdiction, was unlawful, the State Board of Education referred the matter to the Attorney General for appropriate action under G.L.c. 15, § 1G. The Attorney General decided to resort to litigation and, joining with him the Board of Education and the Commissioner of Education, he commenced the present action in October, 1978, in the Supreme Judicial Court for Suffolk County against MIAA, the interrelated Massachusetts Interscholastic Athletic Council (Council), and an individual occupying important positions in both organizations. The plaintiffs prayed a declaration that the quoted rule violates the Massachusetts Equal Rights Amendment (ERA) as well as G.L.c. 76, § 5, and regulations promulgated under that statute, and requested corresponding injunctive relief. After answer, the parties joined in a stipulation of facts, and a single justice reserved and reported the case upon the pleadings and stipulation. We outline the facts as they appear without significant dispute.

Virtually all public secondary schools in the Commonwealth are members of MIAA and, by virtue of what is in effect a delegation of authority by local school committees under G.L.c. 71, § 47, MIAA governs and regulates competitive sports among these schools. Some private secondary schools are likewise members and enter into the same competition. All member schools undertake to submit to the rules promulgated by MIAA; they pay dues to MIAA in proportion to their student populations. (MIAA also shares in the receipts from Statewide tournaments, many of which are held on State-owned property.)

Framing of the rules which cover all aspects of interscholastic sports, including practice time, recruitment, and age, academic, and residence requirements for player eligibility, is in the hands of the Council, whose members, parties defendants here, are drawn from a Statewide association of school committees, and from associations of school superintendents, administrators, and principals. MIAA may recommend rule changes to the Council, and it is the MIAA's executive body, called the Board of Control, that is responsible for enforcement (including interpretation) of the rules, with power to impose a variety of sanctions upon offending member schools, ranging from warning or censure to a year's suspension from interscholastic play. Because the rules are comprehensive in scope, it is evident that their policies reach beyond the interscholastic sphere and to some considerable extent also influence the intramural athletic activities of the member schools.

The rules "recognize" for interscholastic play sixteen boys', and thirteen girls' sports: the names coincide except that baseball, football, hockey, riflery, and wrestling are listed only for boys, and field hockey and softball only for girls. Originally part II, § 1, rule 17, entitled "Boys and Girls on the Same Team," provided for strict sex segregation. By 1976, evidently reflecting regulations promulgated by the State Board of Education, and, more generally, the adoption of ERA in that year, rule 17 had been amended so that a student could not be barred from competing for a place on a team because of sex unless the school provided a "separate but equal" team.

Some schools proceeded on that basis to admit male students to a "girls'" team where there was no counterpart "boys'" team. As there were no boys' interscholastic softball teams, Newton South High School in spring, 1978, pursuant to rule 17, allowed two male students to play on its girls' team. This provoked the Massachusetts Division of Girls' and Women's Sports to protest to MIAA's predecessor organization, and then, on June 6, 1978, to commence suit against that organization with a view to preventing Newton South from competing in the girls' State softball tournament. With that action pending, MIAA recommended to the Council that a subdivision d be added to rule 17 which would prohibit boys from playing on girls' teams. It was adopted (with a nonsymmetrical clause regarding girls playing on boys' teams), effective July 1, 1978, in the following terms:

"With due regard to protecting the welfare and safety of all students participating in MIAA athletics: 1) No boy may play on a girls' team. 2) A girl may play on a boys' team if that sport is not offered in the school for the girl."

The State Board of Education took the view that rule 17(d)(1) could not stand legally in its blanket form, and the present action eventuated. The state of affairs on which the new rule impinged, and the policing of the rule, are described in the stipulation of the parties. When the rule was announced, Easthampton High School, which had no swimming team for boys, was allowing boys on the girls' team (the record does not disclose how many boys). There was a similar situation at Pioneer Valley Regional High School in field hockey, and at Amherst Regional, Greenfield, and Northampton high schools in volleyball. The previously all-female David Hale Fanning Trade School in Worcester had then recently admitted forty-eight boys in a total enrollment of 585. As the school could not field teams exclusively for boys, it allowed boys to play on the girls' softball and basketball squads (again, as with other schools, there is no indication of how many boys participated).

In summer and fall of 1978, administrators at Fanning, Greenfield, and the school district encompassing Pioneer Valley requested waiver of the new rule, or of an interpretive memorandum issued by MIAA on October 31 stating that "[s]chools with girls' teams on which a boy or boys participated during any interscholastic competition must record each contest where 17-d-1 was violated as a loss." The waiver requests were denied, and the Greenfield field and Pioneer Valley volleyball teams, which would have been eligible for tournament competition on their actual won-lost records, were unable to qualify.

Concluding our statement of the case, we have first to note that the parties agree, and we concur, that rule 17(d)(1) must be viewed as "State action" for legal purposes. Second, we may be permitted the comment that the rule attacks a small problem with heavy artillery. In the general run of cases there has been no difficulty, as "separate but equal" teams accommodate the students of both sexes, and no question is raised in this case about the legality of separate but equal teams. Rule 17(d)(2) accepts that where there is no opportunity for a girl on that basis, she may compete for a place on the boys' team. The converse problem apparently has arisen in only a handful of schools and only where there was a girls' team but no boys' team in a particular sport. There has been no demonstration by those defending rule 17(d)(1) that male participation on girls' teams after 1976 was other than limited or that it involved any serious distortion or disruption.

1. Prima facie invalidity of a total ban. In a recent Opinion of the Justices, 374 Mass. 836 (1977), we gave our view of a proposed amendment of G.L.c. 76, § 5, which would have disallowed all participation of girls with boys on the "contact sports teams" of football and wrestling. The Justices' opinion was that "[t]he enactment of [the proposed bill] would violate art. 106 of the Amendments to the Constitution of the Commonwealth [ERA]. The absolute prohibition in the proposed legislation cannot survive the close scrutiny to which a statutory classification based solely on sex must be subjected. A prohibition of all females from voluntary participation in a particular sport under every possible circumstance serves no compelling State interest." Id. at 842. (The Justices reserved the question whether a statute "more limited in its impact" would serve such a State interest; in particular we did not say whether women could be excluded from men's teams in a particular sport if they were provided with equal facilities.) Judging from decisions around the country, we think the view we expressed as to wholesale exclusion of girls from boys' interscholastic teams where no girls' teams were provided would be accepted by the courts in jurisdictions having ERA (see Darrin v. Gould, 85 Wn.2d 859; Packel v. Pennsylvania Interscholastic Athletic Ass'n, 18 Pa. Commw. Ct. 45 [1975]), and generally also by courts applying the less emphatic equal protection or due process clauses of State and Federal Constitutions. See Brenden v. Independent School Dist. 742, 477 F.2d 1292 (8th Cir. 1973); Morris v. Michigan State Bd. of Educ., 472 F.2d 1207 (6th Cir. 1973); Leffel v. Wisconsin Interscholastic Athletic Ass'n, 444 F. Supp. 1117 (E.D. Wis. 1978); Yellow Springs Exempted Village School Dist. Bd. of Educ. v. Ohio High School Athletic Ass'n, 443 F. Supp. 753 (S.D. Ohio 1978); Hoover v. Meiklejohn, 430 F. Supp. 164 (D. Colo. 1977); Gilpin v. Kansas State High School Activities Ass'n, Inc., 377 F. Supp. 1233 (D. Kan. 1973); Reed v. Nebraska School Activities Ass'n, 341 F. Supp. 258 (D. Neb. 1972); Haas v. South Bend Community School Corp., 259 Ind. 515 (1972).

The equal protection guaranty and a fortiori an equal rights amendment condemn discrimination on grounds of sex — whether male or female. Thus in an earlier Opinion of the Justices, 373 Mass. 883 (1977), we said that a proposed statute intended to bar boys from a "girl officers regiment" at a public high school would be unconstitutional by reference to the ERA (it was invalid, we said, under the equal protection standard of review as well). Discriminations against men as such have been condemned in many cases, for example: Commonwealth v. MacKenzie, 368 Mass. 613 (1975) (the law could not punish unwed fathers, while exempting mothers from punishment for the act of begetting: decision before ERA). Orr v. Orr, 440 U.S. 268 (1979) (husbands could not be barred from obtaining alimony available in similar circumstances to wives). Craig v. Boren, 429 U.S. 190 (1976) (impermissible to allow girls to buy 3.2% beer at age eighteen but boys not until age twenty-one). Indeed, even if equal rights provisions could be viewed primarily as a means of eradicating discrimination against women, they tend to protect men as well, because disadvantages suffered by males are often premised on a "romantic paternalism" stigmatizing to women. Although women have been the usual victims of sex discrimination, there are significant exceptions to this generality, for example, legislation imposing harsher criminal penalties on men. In the field of athletics, where opportunities in the past have grossly favored males, it remains the fact that some of the less athletic men have been denied active participation in competitive sports in part because of sex segregation. The prejudice to an individual male is well described in a recent opinion holding — on special Federal grounds not urged by the parties herein — that a high school boy should be allowed to compete for a place on the girls' volleyball team, the only one representing the school in interscholastic volleyball.

It may be predicated, then, that the absolute bar to male participation imposed by rule 17(d)(1) — appearing in remarkable contrast to the generally recognized right of girls as stated in rule 17(d)(2) — is prima facie invalid under ERA or our cognate statute barring sex discrimination in the educational sphere. However, the defendants, after an effort to avoid the whole problem by intimating that the prohibition is in reality not sex-based at all (considered at point 3 [a] below), seek to justify it by suggesting that it forwards the important goals of protecting the safety of players (point 3 [b]), and preserving emergent girls' sports programs from feared inundation by male athletes (point 3 [c]). We examine at point 2 the attitude to be taken constitutionally toward such claimed justifications, and particularly a justification in terms of remedying or compensating for an historical injustice.

2. Standard to be applied to attempted justifications. We have held under ERA that classifications on the basis of sex are subject to a degree of constitutional scrutiny "at least as strict as the scrutiny required by the Fourteenth Amendment for racial classifications" ( Commonwealth v. King, 374 Mass. 5, 21 [1977]), and noted that such classifications are not permissible unless they meet two conditions: they must "further a demonstrably compelling interest and limit their impact as narrowly as possible consistent with their legitimate purpose." Id. at 28. No compelling State purpose could be identified in Opinion of the Justices, 374 Mass. 836, 842 (1977), to justify excluding all females from any voluntary participation with boys in football and wrestling, and a proposed statute with such a ban was thought invalid on its face. Conversely, no State purpose justified banning boys from the girl officers regiment. Opinion of the Justices, 373 Mass. 883, 887 (1977).

We did not confront in either Opinion a discrimination based on sex — now, pursuant to ERA, a category in a constitutional tier at least as high as race — which could lay a claim to having a benign or remedial attitude toward the historically oppressed class. That problem we meet here, in so far as the defendants seek to justify the disability they want to fasten on male students on the ground that it is designed to guard the burgeoning athletic programs for females. Certainly it can be said that no stigma attaches to the boys who would be shut out; they are not branded as unworthy to play alongside girls.

Regents of the Univ. of Cal. v. Bakke, 438 U.S. 265, 287-305, 356-362 (1978), is a point of reference. In the field of race or ethnicity — a program of admission to a State medical school calculated to favor minority applicants — five of the Justices had to consider what if any adjustment of the "strict scrutiny" approach should be made where it was claimed for a discrimination that it constituted "affirmative action" assisting in some degree classes previously disfavored, that it was aimed not at perpetuating inequality but, on the contrary, at eradicating the remains of past discrimination. This was but another way of asking what must be the strength of a justification tendered to overcome the basic abhorrence of classification grounded on race.

One of the Justices in Bakke applied an undiminished "strict scrutiny" standard to the case notwithstanding the special justification asserted for the discrimination in favor of minorities. 438 U.S. at 287-305 (Powell, J.). The other four Justices settled on a level of scrutiny that was "strict — not '"strict" in theory and fatal in fact,' because it is stigma that causes fatality — but strict and searching nonetheless." Id. at 362 (Brennan, White, Marshall, and Blackmun, JJ.). At another place in that joint opinion, the Justices spoke of whether the classification "serve[d] important governmental objectives and [was] substantially related to achievement of those objectives" ( id. at 359), a level of inquiry borrowed from equal protection decisions in the realm of gender. See Califano v. Webster, 430 U.S. 313, 317 (1977); Craig v. Boren, 429 U.S. 190, 197 (1976). This somewhat relaxed standard would still call for a judgment whether the discrimination served an important public purpose and, if so, whether it was proportioned to that purpose and did not result in excessive inequality. The latest expression by the Court on the justification that would be needed to sustain a sex preference indeed says it must be "exceedingly persuasive." Personnel Adm'r of Mass. v. Feeney, 442 U.S. 256, 273 (1979). It is a notable fact, too, that the Court has not intimated that it would apply any lowered standard of review to cases of discrimination explicitly based on sex merely because a remedial or benign explanation was offered.

Conceivably an MIAA rule might be so nicely drawn with attention to purpose and scope that a choice among standards might become critical in deciding the rule's validity. But precise election among standards may not be of the essence here, where we confront an absolute prohibition of a boy's joining a girls' team in any sport and under any conditions. We doubt that such a rule could be sustained under any mentioned approach, or variant. Cf. Opinion of the Justices, 373 Mass. 883, 887 (1977). Least of all may it be sustained in the Commonwealth with a specifically directed ERA, not simply a general equal protection guaranty. Under ERA it is especially fitting, and, we think, required, that any purported justification for a classification based on sex, even one claimed to involve "affirmative action," should be weighed with great care.

3. Purported justifications. (a) Sex as a "proxy" for function. The defendants seem to suggest in the course of their argument that the discrimination under attack is in reality not one based on sex but rather on functional differences deriving in the main from biology, and is thus not proscribed by the ERA. No doubt biological circumstance does contribute to some over-all male advantages. But we think the differences are not so clear or uniform as to justify a rule in which sex is sought to be used as a kind of "proxy" for a functional classification. See Caban v. Mohammed, 441 U.S. 380, 389-391 (1979), and the dissent of Justice Stevens at 403-408; Orr v. Orr, 440 U.S. 268, 281-283 (1979).

Our point is illustrated by Commonwealth v. MacKenzie, supra. There the court struck down a criminal statute that punished fathers but not mothers for begetting children out of wedlock; but we upheld the part of the law designed to establish paternity and the obligation of child support because it reflected functional differences, biologically based, between males and females: childbearing renders obvious the identity of the mother, while the father may easily escape recognition. The classification was "more than . . . sex-based." It reflected "significant circumstantial differences between the fathers and the mothers of illegitimate children"; its scheme did not rely on"'archaic and overbroad generalizations, but, instead, the demonstrable fact that male and female . . . [parents of illegitimate children] are not similarly situated.'" Id. at 617-618, quoting in part from Schlesinger v. Ballard, 419 U.S. 498, 508 (1975) (emphasis in original).

MacKenzie suggests that if all high school boys outstripped all high school girls in all athletic endeavors, total separation might be justifiable; the line would be drawn in truth between students in different ability-groups. But this hardly resembles the situation in athletics today (as, indeed, rule 17[d][2] itself seems to recognize), and it becomes every day less descriptive of it.

The general male athletic superiority based on physical features is challenged by the development in increasing numbers of female athletes whose abilities exceed those of most men, and in some cases approach those of the most talented men. Coordination, concentration, strategic acumen, and technique or form (capabilities of both sexes) intermix with strength and speed (where males have some biologic advantages) to produce athletic results. Cf. Brenden v. Independent School Dist. 742, 477 F.2d 1292, 1300 (8th Cir. 1973). Classification on strict grounds of sex, without reference to actual skill differentials in particular sports, would merely echo "archaic and overbroad generalizations." Schlesinger v. Ballard, supra.

Thus rule 17(d)(1) must be taken to be the intentional use of sex as a discriminant, a practice forbidden by ERA unless somehow excused or justified.

(b) Safety. The defendants argue that the gender-based absolute exclusion is necessary to achieve an important State interest, protection of players' safety. Indeed, "protecting the . . . safety of all students" appears in the preamble of the rule (in company with the vague term "welfare") as the rule's objective. It may be enough to say — as the plaintiffs do — that the defendants have not satisfied their burden of supporting the claim with facts. See Bakke, supra, 438 U.S. at 305, 320. Nevertheless we analyze the claim by reference to law and common sense.

The defendants' argument on the score of safety or health was implicitly rejected in Opinion of the Justices, 374 Mass. 836 (1977), where the proposed ban on girls' participation in football and wrestling was considered invalid. A girl is surely not less exposed to injury as a member of a predominantly male team, than as one of a team predominantly female but with some male players. In any case, a girl is entitled as much as a boy to choose to take a risk, subject always to safety rules and appropriate supervision and equipment. As was said in Hoover v. Meiklejohn, supra, 430 F. Supp. at 169, where it was held that considerations of safety did not justify excluding a qualified girl from a soccer team in interscholastic competition: "Any notion that young women are so inherently weak, delicate or physically inadequate that the state must protect them from the folly of participation in vigorous athletics is a cultural anachronism unrelated to reality."

The defendants offer in their brief a statement by a medical advisor (there is no citation to a publication) that attempts a connection between the presence of male athletes on a team with injury to females. It is replete with stereotypical assumptions and generalities. Cf. Fortin v. Darlington Little League, Inc., 514 F.2d 344, 349-350 (1st Cir. 1975) (rejecting medical testimony intermixing cultural with physical observation). But if we were to indulge an assumption of such a relationship in the rougher sports, what of golf, gymnastics, riflery, skiing, track, cross-country running, swimming, tennis? Risks are not constant. Under ERA, a sex-based exclusion must show a closer "fit" than this.

(c) Protection of girls' participation in sports. Although the preamble seems otherwise directed, the prohibition of rule 17(d)(1) is now sought to be justified as a measure of "affirmative action" needed, so it is alleged, to prevent the swamping of girls' teams by boys of skill and prowess superior to those of girls. But the rule is out of proportion to any looming danger. It represents a sweeping use of a disfavored classification when less offensive and better calculated alternatives appear to exist and have not been attempted.

We neither know, nor are apprised by the record, that the apprehended peril is such as to require so sweeping a prohibition. But even if the claimed fear of inundation because of male advantages in many sports were more solidly based in fact, it would not justify the categorical exclusion of males from any sport, or divisions or "events" of a sport, in which, over-all, they enjoy no or only a slight advantage over females. Gymnastics and swimming (as well as riflery) may be examples.

No less important is the fact that the rule overlooks approaches, short of broad prohibition, that could solve any anticipated problem of boys in substantial numbers displacing girls from competition to the serious detriment of the development of athletics for girls. Use of standards focusing on height, weight, or skill rather than solely on gender represents one such approach: males would thus be admitted who could not dominate the mixed teams or overwhelm the opposition. Admission could perhaps be regulated by handicapping in a sport like golf. On another level also, lesser measures than complete exclusion suggest themselves. Where boys' teams were not feasible, admission of boys to girls' teams could be limited, not to exceed reasonable numbers. In particular situations, rotating systems might be adopted by which qualified boys were admitted but only a certain number could play in a given game.

We emphasize that resort to a separate team for boys acts as a backstop for many if not all alternatives which result in introducing boys into girls' teams. That is to say, if enough boys are interested in a sport to try out for, and threaten to oust girl players from, a particular team, the school authorities are on notice that a boys' team may be in order. Should the number of boys be not quite enough for a separate squad, the problem would sometimes be amenable to solution by forming a consolidated boys' team representing neighboring schools (see n. 17). As noted earlier, the legality of segregation in separate but equal teams is not challenged here.

We do not overlook the difficulties in maintaining fair competition when mixed teams enter the lists, but it would be premature to assume that the difficulties are insurmountable. That assumption might itself stem from stereotypes which ERA rejects. Some of the mixed teams will have been so constituted in the first place that they will compete with no advantage. Handicapping as well as selective pairing of teams may be feasible for other cases. During a period of experimentation and change, some unevenness in the competition may result, but that calls merely for a modicum of toleration and some imaginative willingness to try new combinations.

Our mention of alternative patterns is intended merely to throw light on the question of the constitutional validity of the Draconian choice made by the defendants. We acknowledge very freely that the defendants are far abler than ourselves to decide what means they need to adopt to promote athletics, and girls' athletics in particular, once the constitutional limits have been set down. As Justice Blackmun said in Bakke: "The administration and management of educational institutions are beyond the competence of judges and are within the special competence of educators, provided always that the educators perform within legal and constitutional bounds." 438 U.S. at 404.

4. Summing Up. The State Board of Education, through the Attorney General, has rightly questioned a rule of the MIAA which would bar boys from playing on girls' interscholastic teams — an absolute rule applying by its terms even when no comparable boys' team exists. Any rule which classifies by sex alone is subject to close examination under the concept of equal protection of the laws, as that has been strengthened by the popularly adopted ERA and the statute on educational opportunity. Upon such examination, no current situation confronting MIAA has been pointed to that would warrant so drastic a rule of exclusion. An alleged "safety" justification for the prohibition must fail. A further justification alleged was that, without a total ban on all participation by boys, girls' sports would be overrun by boys who as a class are physically better equipped for athletic competition. Undoubtedly there is a problem here which is entitled to sympathetic consideration and to the extent necessary may even call for "affirmative action." On analysis, however, it appeared that the problem was marginal; where it arises, it can be met by measures less offensive and less sweeping than a complete sex barrier.

It can be expected that the present decision will make little practical difference in the traditional conduct of interscholastic athletic competition, for that will proceed in the great majority of instances on a basis of "separate but equal" teams whose validity is assumed here. We do not believe our decision will interfere with the development of competitive athletics for girls. On the contrary, to immunize girls' teams totally from any possible contact with boys might well perpetuate a psychology of "romantic paternalism" inconsistent with such development and hurtful to it in the long run.

The present decision is addressed to the facts as they now appear. We acknowledge that future changes in the situation, not now perceptible, may call hereafter for a different solution.

The case will be remitted to the single justice for the entry of judgment declaring rule 17(d)(1) to be invalid and appropriately enjoining its application.

So ordered.