(SAN FRANCISCO, CA) -- The explosive growth of Internet sex -- ranging from pornographic Web sites to steamy chatrooms -- may be creating a group of people with sexual compulsions they cannot control, according to a study made public on Tuesday.

``For the vast majority of people, sexuality online is not going to be a problem, but for some people it is going to be a big problem,'' said Dr. Al Cooper of the San Jose, California, Marital and Sexuality Center.

Women, gay men and other ``sexually disenfranchised'' groups were at particular risk for Internet sex addiction, said the study -- which indicated that, for some users, the Internet's cornucopia of sexual offerings may prove overwhelming. ``The Internet... is the first place where (these groups) have true freedom and total access to an unlimited amount of sexual materials,'' Cooper said in an interview.

``They may not have the same skills built up that heterosexual men have on dealing with sexual temptation and pornography. It's like unleashing them in the candy store.''

Cooper, along with colleagues Ron Burg and David Delmonico, reached their conclusions after examining the results of what was billed as the world's first major ``click-and-tell'' survey on sex and the Internet, which was conducted in 1998 on the MSNBC Web site.

Earlier analysis of the some 9,000 validated responses showed that more than 90 percent of respondents spent less than 10 hours a week on cybersex, pouring cold water on the idea that most of the millions of daily Internet users were surfing for pornography.

But Cooper and his colleagues, in a study to be published in the March issue of ``Sexual Addiction and Compulsion: The Journal of Treatment and Prevention,'' found that for some subsets of Internet users, the temptation could be great.

Using relatively conservative measures, the researchers concluded that about 1 percent of the respondents could be classified as true ``cybersex compulsives'' -- spending more than 11 hours a week on online sex -- and that more could well be at risk as Internet use expanded.

``In some ways that seems small, but when applied to the big picture it could represent hundreds of thousands of individuals,'' Cooper said. ``Compared with a few years ago, that would mean 120,000 new addicts. It's an epidemic that nobody is talking about.''

Along with women and gay men, Cooper says students appear to be at a relatively high risk for developing sexual compulsions focused on the Internet.

``They have freedom for the first time in their lives, they have more free time and they are given this very powerful type of thing that is the Internet and combine it with sex,'' Cooper said.

``They might not have the skills they need to protect themselves from getting into trouble,'' he added.

While almost 79 percent of poll respondents said they confined their Internet sex to their home computers, Cooper said more people appeared to be pursuing so-called cyberotica from the workplace.

``Our research indicated that 20 percent of men and 12 percent of women use their work computer to access online sexual material,'' the researchers reported, adding that six out of every 100 employees admitted that their work computers were their primary method for accessing online sexual material.

Some experts have questioned the validity of Cooper's findings, noting that the self-selecting nature of the respondents meant it was not as scientifically useful as a true, random poll. Editors at MSNBC said they posted the survey for fun and not to obtain hard scientific results.

But Cooper, a psychologist who teaches at Stanford University, said the fledgling field of online sexuality studies required new methods of gathering data and that Internet polls could reach a much larger and more diverse group than traditional surveys.