An Idaho newspaper reporter was jailed for 7 1/2 hours today in the latest in a series of press-vs.-court conflicts over reporters' rights to protect confidential sources.

The reporter, Ellen Marks of the Idaho Statesman, refused to answer numerous questions in connection with her coverage of a convoluted divorce-custody dispute. A woman in hiding is accused of kidnaping her own daughter to keep her from the alleged influence of a religious cult.

Marks, appearing in court this morning, refused to testify about the whereabouts of Geni Gilmore, the mother of the 8-year-old child.

"Based on journalist ethics, the First Amendment freedom of the press and my agreement to keep the whole situation confidential, I refuse to answer," said Marks.

Fourth District Court Magistrate Karen Vehlow cited the reporter for contempt and ordered her jailed without bond.

Vehlow said reporters have no special privilege and must answer questions in court like any other citizen. "I don't feel incarceration is unreasonable," Vehlow told a hushed courtroom. "I don't enjoy doing it. It is called for."

The interests of the child are more important than a reporter's claim of privilege, the judge said.

Marks' attorneys filed an appeal in Idaho's Fourth District Court, an action that automatically allowed her to go free for seven days pending action. Seven and a half hours after entering the county jail, Marks walked out, to the cheers of her colleagues.

The incident stirred new protests of court intrusions into the news-gathering process.

Jack Landau, director of the Washington-based Reporters Committee for Freedom of the Press, called the Marks jailing "ridiculous."

"Throwing reporters in jail in what amounts to a public custody dispute is only going to discourage reporters from seeking out similar stories," he said. "If Marks can be thrown in jail for refusing to disclose the whereabouts of a source, what about the next reporter who does a story complaining about the court system?"

Similar conflicts have landed other reporters in jail. Myron Farber, of The New York Times, was jailed in 1978 for refusing to yield to a New Jersey judge confidential files in a celebrated murder case. He served 26 days before being released.

Mark McKinnon, student editor of the University of Texas Daily Texan, was jailed briefly last January for refusing to give up unpublished photos taken during a protest.

Twenty pending cases involve contempt of court charges against reporters trying to protect their sources, said Ben Ginsberg, an attorney for the reporters committee.

Marks' jailing stemmed from a custody case in which the divorced woman took her daughter into hiding rather than return her to the father, a onetime member of Guru Marharaj Ji's Divine Light Mission. The woman's husband, meanwhile, has been jailed for refusing to tell where she is.

The principals in the case, Geni and Michael Clary, were divorced in Nebraska in 1975, and he was awarded custody of their daughter, Alysia. Geni married Randy Gilmore and moved to Idaho.

When the child visited the Gilmores in Idaho this past summer, the couple found her listless, immature and not sociable. Geni Gilmore believed her ex-husband's ties to the religious cult were harming her daughter, and decided not to return her to him.

"We feel real responsible for her, and we don't want to see her go back to the situation she was in," she told Marks in a Sept. 12 interview.

Geni Gilmore blamed Clary's involvement in the cult for disrupting their family life before their divorce.

Clary says he's no longer a member of the cult, although he accepts some of its basic precepts. He says he has exposed his daughter to a variety of spiritual philosophies, but never pushed his beliefs on her.

He came here to press for his daughter's return, and Judge Vehlow ordered the Gilmores to give her back. But, two days before the appointed date of Sept. 10, Geni took her daughter into hiding. Randy Gilmore showed up in court, but did not tell where they were, and was jailed without bond on contempt.

Geni Gilmore now faces a second-degree kidnaping charge, and an arrest warrant has been issued. In the interview that ultimately led to reporter Marks' jailing, Geni Gilmore said she didn't think she would come out of hiding, for fear of Alysia's fate if she returns to her father.

"Giving her back does not seem the thing to do," she said.