The National Women's Law Center yesterday urged the Senate to reject the nomination of Robert H. Bork to the Supreme Court, saying that his judicial record is "unparalleled in its hostility to women's rights" and that he would challenge the legal rights women have gained in the 20th century.

Marcia D. Greenberger, the center's managing attorney, said the Washington-based group had never taken a position on any judicial nomination, but, "In this instance, we could not in good conscience remain silent . . . . Judge Bork's views reflect America of the 18th and 19th century, where under the law women stood behind men -- not by their side."

Bork, President Reagn's nominee to replace retired justice Lewis F. Powell Jr., had no comment.

In the center's 39-page analysis of his legal record, Bork is criticized for his 1985 dissent, as a judge on the federal Court of Appeals here, on Vinson v. Taylor, a major sexual harassment suit in which the Supreme Court later decided unanimously that a woman who was faced with the loss of her job if she did not succumb to the unwelcome sexual advances of her supervisor was a victim of sex discrimination.

In that case, Bork called the classification of sexual harassment as discrimination "awkward." He went on to say, "Harassment is reprehensible, but Title VII {which bans sexual discrimination} was passed to outlaw discriminatory behavior and not simply behavior of which we strongly disapprove."

The center argued that Bork also rejected the Supreme Court's key 1971 decision in Reed v. Reed in which the court for the first time held that it was a denial of the equal protection clause of the Constitution for a state to give preference to men automatically over comparably qualified women in appointing administrators for certain estates.

But Bork, writing about his interpretation of the equal protection clause in 1971, said it "does require that government not discriminate along racial lines. But much more than that cannot properly be read into the clause."

In a 1982 speech, he added, "When they {the courts} begin to protect groups that were historically not intended to be protected by that clause, what they are doing is picking out groups which current morality of a particular social class regards as groups that should not have any disabilities laid upon them."

The center also criticized Bork's statements that the constitutional right to privacy is not based on the "original intent" of the Constitution's framers and is therefore not supportable.

Bork has been critical of Supreme Court rulings upholding affirmative action, abortion rights, the right of married couples to obtain birth control and other decisions favoring civil and social rights.