CHICAGO -- Porn used to be relegated to a video hidden in the bottom drawer or a magazine under the mattress. Today, it's part of everyday life.

Hugh Hefner's girlfriends have become TV's "girls next door." Porn stars have MySpace pages and do voiceovers for video games. And while "porn on demand" is standard for hotel-room TVs and upgraded cable packages, it's even easier to find it with a few clicks on the computer.

In April, more than a third of the U.S. Internet audience visited sites that fit into the online "adult" category, according to comScore Media Metrix.

So the message is clear: In today's world, sex doesn't just sell. The pervasiveness of porn has made sexiness -- from subtle to raunchy -- a much-sought-after attribute online, at school and even at work.

Peter Hirschburg, a sociologist at Southeast Missouri State University, said accessibility to porn has increased, but drawing correlations with porn use and social problems is easier said than done.

The three finalists in last month's "talent search" contest for the Internet's "Naked News" posed in New York. They were, from left, Valentina Elizabeth, Kortney Kaiser and Holly Eglinton. Eglinton was the eventual winner. A self-proclaimed "poser," Eglinton sees the chance to take her clothes off online as fun, empowering and a little rebellious -- though others wonder if the trend toward exhibitionism has gone too far. (Naked Broadcasting Network Inc.)

"The nature of sex has changed in the past 40 years," Hirschburg said. "It's awfully hard to show that it's pornography and nothing else causing negative behavior."

Hirschburg said there are theroies that porn desensitizes people to sex and the nature of sex, but they haven't held up to scrutiny.

"Pornography is difficult to define in a legal sense," Hirschburg said. "Also, for a true causal relationship to be established in a scientific sense, many things must be established."

Hirschburg said a statistical correlation must be shown between the negative outcome, emotional issues related to body image, and the suspected cause, increased access to pornography.

Other possible causes must be eliminated and a higher incidence in emotional issues would have to have occurred after the internet porn appeared.

Hirschburg said pornography's existence thoughout history makes establishing such a connection difficult.

Mike Cowen, principal of Cape Girardeau Central High School, said pornography was an issue with students long before the internet allowed easier access.

"Twenty-five years ago, when I started teaching, I had to take away adult magazines from students," Cowen said. "We have a filter on our school computers that blocks almost all adult sites. A few people have gotten through, but we've dealt with those cases, and it hasn't really been an issue."

Many agree, however, that the trend has had a particularly strong influence on young women -- in some cases, taking shape as an unapologetic embracing of sexuality and exhibitionism.

The fascination with being "hot" also has made its way into the workplace, where confidence is often conveyed in the way one looks and dresses.

Southeast Missourian staff writer Peter Wylie contributed to this report.