Bob Jones III didn't exactly turn the other cheek to the Supreme Court.

Last Tuesday, the court ruled that the IRS could take away the tax exemptions of private schools, including his own, that discriminate on the basis of race. The same day, the reverend sermonized, "We're in a bad fix in America when eight evil old men and one vain and foolish woman can speak a verdict on American liberties."

In this one charming sentence, the man enhanced his own reputation for tolerance toward women as well as blacks.

But there may have been more implications for sex discrimination in this case than Bob Jones's slurs. A familiar question has been raised by this decision. If a private school that discriminates against blacks can lose its tax-exempt status, what about a school that accepts only one sex?

Today there are only a handful of all- male colleges in the country. But there are 110 women's colleges. Their reason for being, the justification for public support, the legal status of these schools has been debated in and out of court by lawyers, educators, women's rights advocates and public policy-makers.

In 1981, the town of Whately, Mass., in a fit of pique over a tax bill, challenged Smith College's tax-exempt status on the grounds of sex discrimination. The case was lost by the town, but the issue of sex discrimination was never resolved.

Last year (in the Hogan case) the Supreme Court ruled that an all- women's nursing school supported by the state of Mississippi had illegally refused admission to a man. The decision--written by the same "vain and foolish" woman--emphasized the fact that this man was truly harmed.

At the moment, there is no case pending against a women's college, but this is a tricky philosophical issue for women's rights supporters. Most of these women's colleges have been in the forefront of the fight for equality and integration. Yet they are now vulnerable to charges of discrimination.

Marcia Sharp is director of the Women's College Coalition, which has been dealing with just this question. She says: "The intellectual puzzle is that these women's institutions were founded as places where women could develop higher aspirations. They support equal rights almost more than any other institution in society. Now they are in the ironic position of perhaps being called into question by the same drive to equity."

The Supreme Court based its ruling against both Bob Jones University and the Goldsboro Christian Schools on established public policy against racial discrimination. The Goldsboro schools were set up deliberately to keep out blacks. Ninety-nine percent of the time, segregation is the policy of exclusion, a handmaiden of inequality whether we are talking about race or sex.

But women's colleges were established in reaction to exclusion. Today, these 110 colleges still do more to promote equality of the sexes than to deny it. They have produced more women leaders, scientists and educators than their fair share.

As Nan Keohane, the president of Wellesley College, says: "Our argument is that women's colleges enhance opportunities for women."

To reduce public support for women's colleges in the name of equality would, as Phyllis Segal, the longtime NOW Legal Defense and Education Fund counsel, says, "be a myopic view of what equality requires. You can't confuse ends and means."

Many women express ambivalence on this subject. Women who have fought to break into all-male professions and institutions are uneasy defending all-female institutions. Mary Gray of the Women's Equity Action League is challenging sex- segregated public high schools in Pennsylvania, while favoring tax-exempt status for women's colleges. "I don't think it's easy in any sense of the word," she says.

The strongest and least tortuous argument is the affirmative action or "affirmative effort" defense. Come the evolution, women's colleges may be irrelevent, sexist anachronisms. But in this transitional period, these single- sex seeding grounds deserve special treatment.

As Wellesley's Keohane says, "The case we're making is that we are providing a different route toward the same goal." It's a route that may take women's colleges over a lot of legal potholes.