Half a century ago, Alfred Kinsey, the father of American sex research, published a report that revolutionized sexual mores, liberating discussion of sex and challenging centuries of beliefs about human appetites and capacities.

Yesterday, the director of the Kinsey Institute revealed that Kinsey's conclusions on the sexuality of young children were based not on scientific study but on the secret history of a single pedophile who kept a diary of his experiences with 317 pre-adolescent boys.

Now a group of religious conservatives, backed by a House freshman not exactly known for his rhetorical restraint, argues that the sexual revolution of the latter half of this century is based on a fraud and must be reversed. No Kinsey, no sex education, they say. If man is not a sexual animal from the beginning, why teach children about condoms?

John Bancroft, director of the Kinsey Institute for Research in Sex, Gender and Reproduction at Indiana University in Bloomington, made the "clarification" about Kinsey's methods after a Washington press conference at which Rep. Steve Stockman called Kinsey a fraud who used pedophiles to molest children for studies that should now be considered as tainted as Nazi medical experiments. Stockman, a Texas Republican, called for a congressional investigation into Kinsey's pioneering 1949 report.

In "Sexual Behavior in the Human Male," the first major attempt to measure scientifically the range of human sexuality, Kinsey included two tables documenting pre-adolescent sexual experience. The findings were "an important substantiation of the Freudian view of sexuality as a component that is present in the human animal from earliest infancy," Kinsey wrote.

But as Bancroft said in an interview yesterday from his office in Bloomington, Ind., "the material in the tables came from one man, an extraordinary man with incredible numbers of sexual experiences on which he kept very careful notes."

Nowhere does the Kinsey report reveal that its conclusions on the sexual capacity of a sample of 317 young boys are based solely on evidence provided by one man, and nowhere does the report reveal that that the man was a pedophile -- or, as Bancroft calls him, "an omniphile, an extraordinarily active man."

"Kinsey gives the impression that the data came from three or four men, but it was just the one," Bancroft said. He speculates that Kinsey kept that bit to himself because he thought the public might not react well to his use of data from a sex criminal. "How valid this information is, obviously one could argue about now," the director said.

Kinsey's text is more than a little evasive on the source of his information. He says that nine of his "sources" observed pre-adolescents having orgasms, and adds, "Some of these adults are technically trained persons who have kept diaries." In fact, Bancroft says, there were not nine sources but just the one, and that man's training was in forestry.

Half a century later, Stockman and the Family Research Council, a Washington conservative group dedicated to restoring "family values," seek to show that Kinsey's methods utterly discredit his theories of human sexuality, in turn destroying the foundation of contemporary attitudes toward sex education, sex outside marriage and tolerance of homosexuality.

Stockman's questions stem from the writings of an independent researcher in Arlington who has campaigned for 14 years against the Kinsey report. Judith Reisman has argued repeatedly that Kinsey's findings cannot describe normal sexual behavior because they are based on evidence collected in good measure from prison inmates.

"If the public learns the truth," she said yesterday, "the sexperts' in the field of human sexuality and the sex industry will be shaken to its foundations. . . . Whole shelves of books will have to be rewritten. Both public and religious schools will have to discard their sex ed courses. Lucrative public grants will dry up."

Reisman brought her campaign to the Family Research Council six years ago, and earlier this year the organization produced a half-hour documentary, "The Children of Table 34," a reference to the chart in the Kinsey report labeled "Examples of multiple orgasm in pre-adolescent males."

The video, which Stockman said "moved me greatly," opens with actor Efrem Zimbalist Jr. standing in a courtroom, intoning heavily: "What would you think if you learned that some of the most important scientific research of the century may have been based on fraud, or if not fraud, criminal experimentation on children funded by the taxpayer?"

"What happened to Dr. Kinsey's small subjects?" Zimbalist asks. "Where are the Children of Table 34?"

No one will ever know, because no one but the pedophile ever knew, Bancroft says. "There was no contact with any of the boys by anyone at the institute, only with the man's notes," he said. The institute "has never carried out sexual experiments on children." As for the pedophile -- who was not paid -- he is catalogued at the Kinsey Institute under a pseudonym, which could be decoded but will not be if Bancroft has anything to do with it. "The man is long dead. He died around 1955," the director said.

"This whole thing is a totally spurious attack," Bancroft insisted. "The idea that the writings of one man is the total basis of sexual education in the United States is a total nonsense. These are old allegations that have been answered. It's been taken up as a way of attacking sexual education and nothing more. There are many things I could say about Judith Reisman, but you'll excuse me if I don't."

Several years ago, Reisman sued the institute for defamation of character. Her suit was thrown out of court, Bancroft said.

Stockman embraced the Kinsey issue after viewing the video, and at the suggestion of one of his staffers, William Witten, who once worked as a researcher for Reisman.

Yesterday, Stockman accused the Kinsey Institute of erecting "a wall of silence" preventing investigators from learning more about the research on children. But Bancroft and Christopher Simpson, special counsel to the president at Indiana University, said Stockman and his staff repeatedly spurned their efforts to find out about the studies.

After someone faxed Simpson a copy of Stockman's "Dear Colleagues" letter on the Kinsey matter, Simpson says he called Stockman's office and spoke to Witten.

"Witten said, We don't have any more questions for you,' and hung up," Simpson said. "I have been calling them for two days now, and of course they have not returned my calls."

Stockman said he first heard from the Kinsey Institute Wednesday "at 5 o'clock. The horse was out of the barn and now they want to talk? Sorry, too late."

The congressman compared Kinsey's use of a pedophile's notes to the government's use of Agent Orange in Vietnam and its LSD experiments on unwitting citizens, saying that federal funding of Kinsey's research gives the government the obligation now to flush out the truth about the sex studies.

Robert Knight of the Family Research Council said Kinsey received grants from the National Research Council of $40,000 a year.

But institute records show that that money was just passed along by the federal agency and that the funds came from the Rockefeller Foundation. "The Kinsey Institute did not receive a dime of federal money until after Kinsey died, because Dr. Kinsey was opposed to accepting it," Simpson said. "Representative Stockman's office knew this. Representative Stockman is just the latest person to circulate these old, patently false allegations."

Bancroft says the accusations against Kinsey are designed not to root out academic dishonesty but to advance an ideological agenda.

Stockman called the Kinsey research "an affront to humanity," but he shied away from embracing entirely the message of his guests at the news conference. Asked whether any discrediting of Kinsey's work should invalidate sex education in American schools, Stockman took a step back, paused, and said, "That's another whole area. Right now we want to be looking for the victims."

The emphasis on the victims of the anonymous pedophile is the dramatic core of the Family Research Council video, in which a psychologist pleads for those children to come forward. None ever has. CAPTION: Researcher Alfred Kinsey in 1953. His influential 1949 sex study is under attack for its reliance on one pedophile's diary. CAPTION: Rep. Steve Stockman, who calls Kinsey a fraud, and the cover of "The Children of Table 34," the Family Research Council's video attacking Kinsey's sex study.