The Supreme Court yesterday let stand an appeals court decision striking down an Illinois law that would have restricted the right of teen-agers to have abortions by requiring them to notify their parents.

The 4-to-4 decision, with no accompanying opinion, means the court could reconsider the issue when there are nine members and underscored the critical role Supreme Court nominee Anthony M. Kennedy could play on the abortion issue if he is confirmed. The tie vote means the ruling sets no nationwide precedent.

Edward Grant, executive director and general counsel of Americans United for Life, called the ruling "a defeat for the rights of parents and the interests of minors in Illinois." But he added, "The fact that we got four votes is encouraging."

"Basically it reaffirms the ideological split on abortion," said Janet Benshoof of the American Civil Liberties Union's Reproductive Freedom Project. " . . . I hope there's a trickle-down effect, even though there's no precedential value. At least they didn't go backwards.

"This makes it clear that Kennedy is an edge-breaker on the issue of abortion. Kennedy is on the line on this issue," she said.

Although there was no recorded vote, legal experts said yesterday that based on a process of elimination, they believe that Justice Antonin Scalia, the newest member of the court, cast one of the four votes against overturning the law, providing the first glimpse of how he may rule on the abortion issue in the future.

Grant said the Supreme Court is likely to get another chance to deal with the issue, since there are at least six other cases before the federal courts dealing with similar questions.

More than 20 states have passed laws requiring parental notification before minors can obtain abortions. About half of the laws, including the one in Illinois, are not in effect because of court injunctions.

The 1983 Illinois law, which was enacted over the veto of Gov. James R. Thompson, required females under 18 who are still financially dependent on their parents to notify both parents or a judge at least 24 hours before obtaining an abortion.

It allowed a teen-ager to avoid notifying her parents if she could convince a state judge that informing her parents was not in her best interests and that she was mature and well-informed enough to make the decision on her own. Doctors who failed to comply with the law would have faced criminal prosecution.

The law was struck down by the federal courts before it went into effect on the grounds that it was too much of a burden on minors seeking abortions.

A similar case is pending before the 8th U.S. Circuit Court of Appeals concerning a 1981 Minnesota law -- also overturned by a District Court -- that is almost identical to the Illinois law except that it requires a 48-hour waiting period after the parents are told.

A 1981 Supreme Court decision allows states to impose parental-notification requirements for "immature" girls still dependent on their parents. In that ruling, the justices said girls may avoid notifying their parents by getting a judge's permission instead. In a 1983 ruling, the court struck down a 24-hour waiting period that applied to minors and adults alike who sought abortions.

The Supreme Court's landmark 1973 ruling in Roe v. Wade established the constitutional right to an abortion in certain situations.

In the Illinois case, the lower court held that the new law was unconstitutional. The appeals court, following the lead of the Supreme Court's 1983 decision, held that the 24-hour waiting period was unconstitutional. It did not eliminate the section dealing with parental notification, but it held that that portion of the law could not be enforced until the Illinois Supreme Court worked out a system of "expeditious and confidential" judicial hearings for girls who wanted to avoid notifying their parents.

"It's as though the court had not taken the case . . . , " said Laurence Tribe, a Harvard Law School professor and authority on the Supreme Court. "{But} it does not seem unexpected. Most observers thought the court would be evenly divided on this extension of Roe v. Wade."

In other action yesterday, the court:

In a 6-to-2 vote in a case involving three Virginia miners, made it easier for coal mining companies to block the award of "black lung" disease disability benefits to miners.

Refused to hear an appeal by a Kentucky public high school teacher fired for showing her class "Pink Floyd -- The Wall," an R-rated movie about a troubled rock star.

Ruled unanimously that labor disputes settled informally by the National Labor Relations Board's chief lawyer may not be appealed in federal court.

Agreed to review Ohio's promotion through tax credits of the use of gasohol. The tax-credit system is being challenged by a gasohol producer in Indiana as an unfair interference with interstate commerce.