THE REVOLUTION inches resolutely forward. This fall, in Maryland, girls will be permitted to try out for the high school football teams. Perhaps not many will want to. But the point is that a regulation used to forbid it, and the regulation has now been abolished by the State Department of Education. Girls will also be able (legally, at least) to go out for wrestling, lacrosse and any other body-contact sport. While girls can try out for football, boys will not be permitted to step through the same door in the other direction to play field hockey or volleyball.

Formally, the school authorities justify the one-way door by arguing that the range of athletic opportunities has been much wider in the past for boys than for girls, and it is necessary to overcompensate now. The reality is , of course, much more obvious. High school boys tend to be bigger and stronger than girls. It's an inequality that the law can't do much about. If the boys chose to do it - and who knows what high school boys might not choose to do? - they could take over the volleyball teams. It's the familiar riddle. The pursuit of equal opportunity seems to create its own inequalities along the way.

Over the past five years there has been a huge shift of resources in school systems throughout the country toward the greatly neglected woman's sports. The famous Title IX of the 1972 Education Act prohibited discrimination by sex, and in the same year Maryland cratified its won constitutional amendment guaranteeing equal rights. That resolved everything excepts, as usual, the definition of "discrimination." The Department of Health, Education and Welfare held that, in view of one thing and another, etc., sports did not have to desegregate body-contact sports. Wrestling clearly is a body-contact sport, and golf clearly isn't. But what about soccer?Some regional offices of HEW said it was, and some said it wasn't. Around here the schools considered it a body-contact sport, but boys and girls have played together for years in the local neighorbood and couty soccer leagues. This week the harassed Maryland school authorities threw up their hands and abandoned the body-contact rule altogether.

At the present stage of the revolution, inter-scholastic tennis will match girls only against girls, but will permit mixed doubles. In track, there will continue to be separte boys' and girls' event because it's always been that way. The two sexes will play basketball separately on grounds that there are established teams for each. But there may be some interesting changes coming in soccer and, possibly, baseball, for there are no separate girls' teams in those games. But sexist rules will continue to keep boys out of hockey or softball.As for football, that is very likely to remain firmly segregated for reasons that the egalitarians among us deplore, but that remain beyond legal regulation to amend.

Simple equality? You have occasionally heard the phrase. But, you will notice, it is a contradiction in terms.