Lawyers for Georgetown University argued yesterday in D.C. Superior Court that because the school is a religious institution, it is exempt from the D.C. Human Rights Act, which prohibits discrimination because of sexual orientation.

Two homosexual rights groups have sued Georgetown, arguing that it discriminated against them by not allowing them to use university facilities in the same manner that it allowed other student groups to maintain offices on campus.

Retired D.C. Superior Court Judge Leonard Braman ruled last March that the school was in an "unmistakable violation" of the D.C. law by not recognizing the two organizations.

But Braman did not address the issue of whether First Amendment protections of freedom of religion allow the school to withhold recognition of the homosexual groups. That is one of the issues Judge Sylvia Bacon, who took over the case from Braman, is being called upon to decide in a case that lawyers for both sides say could be a major clash of First Amendment protections.

The university filed papers in court arguing that the main issue is whether Bacon, who adopted Braman's ruling as her own, has the power "to force the oldest Roman Catholic University in the United States to endorse officially student organizations, when the philosophies, activities, and goals of those organizations are utterly inconsistent with the traditional teachings of the Roman Catholic Church on human sexuality."

Ron Bogard, one of the attorneys for the groups, argued that Georgetown was singling out the homosexual organizations for what he called "garden variety" discrimination.

The university has neither prohibited the groups--the 50-member Gay People of Georgetown and the Gay Rights Coalition of the Georgetown University Law Center, which has about 20 members--from meeting on university property nor barred members from attending the school, both sides agree.

But the university's position, as stated in a recent letter to the faculty from its president, Timothy S. Healy, is that official recognition of the groups "would involve the public endorsement of both groups . . . and put the university in a position of saying that homosexuality is merely an alternative life style. Georgetown cannot do this without denying its own tradition and being."

Bogard argued in court yesterday that there can be no logical connection between university recognition of the groups and university sanctions of the groups' activities. Bogard said the university recognized Jewish student groups that may invite speakers from radical Jewish organizations and women's groups that may promote the use of birth control devices or discuss abortion at their meetings. Those groups do not necessarily espouse the teaching of the Catholic church, but they "do not have their charters revoked," Bogard said.

Neither side got far into its arguments yesterday in the 90-minute hearing before Bacon. But the trial, which is expected to end some time next week, will also involve arguments about whether Georgetown is in fact a Catholic institution.

In their lawsuit, the student organizations cited a 1906 U.S. Supreme Court case in which the university argued that it "was difficult to imagine . . . under what theory it can be successfully contended, or even seriously argued, that Georgetown is a religious or denominational institution."

The school's lawyers yesterday said that case "had nothing at all to do with whether Georgetown was sufficiently affiliated with the Catholic Church to assert a First Amendment claim ." A school may "have ties to a church and a faith tradition," the lawyers argued, and still, for example, receive federal aid.