LOS ANGELES -- Hollywood and the media may portray American culture as a cauldron of steaming sexuality, but the private lives of Americans are more like a comforting bowl of warm oatmeal.


A landmark study of adult sexuality in the United States has found that the sexual practices of Americans are surprisingly conservative. It is a portrait of a land of faithful partners who have sex conventionally, about once a week.


The research -- billed as the most comprehensive look at the subject ever -- disputes many widespread myths about sexual practices in the United States, researchers at the University of Chicago said. They added that the results will help Americans deal with a number of public policy issues related to the spread of AIDS, increasing numbers of abortions, teenage sexuality and the future of marriage.


Among the findings:


?Though Americans have sex once a week, on average, a full third have it only a few times a year or not at all.


?More than 80 percent had only one sexual partner or no partner at all in the past year, and just 3 percent had five or more partners during that period.


?Only 2.8 percent of men and 1.5 percent of women said they were homosexual or bisexual, well below some previous estimates.


?Some 72 percent of women who have undergone abortions have had only one. This disputes the idea, the researchers say, that abortion is routinely used as a form of birth control.


The researchers also conclude that the high degree of monogamy, linked with the observed patterns for selection of sexual partners, make it unlikely that AIDS will spread through the heterosexual population in the epidemic fashion some experts have predicted.


The findings are contained in two new books, one for scientists to be published Monday and one for the lay public to be published the next Monday.


The study, gleaned from 90-minute personal interviews with 3,432 adults, represents the broadest scientific sampling yet of Americans' sexual practices and attitudes, say the authors. Prior works such as Shere Hite's "The Hite Report,'' and large-scale sex surveys in publications such as Playboy promoted a ``myth'' that Americans are more sexually active than they are, the books say.


"America has a message about sex, and that message is none too subtle,'' write the authors of "Sex in America.'' "Anyone who watches a movie, reads a magazine, or turns on the television set has seen it. It says that almost everyone but you is having endless, fascinating, varied sex.


"But, we have found, the public image of sex in America bears virtually no relationship to the truth. The public image consists of myths, and they are not harmless, for they elicit at best unrealistic and at worst dangerous misconceptions of what people do sexually.''


Some of the results should be very encouraging to anyone who honors family values, according to sociologists Edward O. Laumann and Robert Michael, leaders of the team that conducted the study. Almost all Americans marry, and 75 percent of married men and 85 percent of married women say they have remained faithful.


(LAT, Newsday)