While America was riveted on a murderous love triangle featuring a female astronaut driving 900 miles wearing a diaper, another significant story received little notice.

A new study reports that 42 percent of Internet users between the ages of 10 and 17 have viewed online porn.

Another day. Another blip. America shrugs.

Porn has gone so mainstream that we hardly flinch at its mention anymore. No longer the dirty purview of the sleazy fringe, it's everywhere — in hotel rooms, on the Internet, in America's video cabinet.

But 10-year-olds?

I don't much care what adults do on their own time in their own space. But everyone — especially children — has a right not to see. Not to know.

These recent findings, published in February's Pediatrics, are the result of telephone interviews with 1,500 Internet users. The University of New Hampshire researchers found that two-thirds of those exposed to porn didn't want to see the images and didn't seek them out. Most of these were ages 13 to 17, though a disturbing number were 10- and 11-year-olds.

Such research is relatively new because online porn is relatively new. Most adults over age 30 didn't grow up in a world where porn was so readily accessible. Today's raunchy new world forces a new question: Are children harmed by watching porn?

Once upon a time when grown-ups roamed Planet Earth, no one had to ask that question. Of

course viewing porn is harmful to children, who by definition are emotionally and psychologically unformed.Images of two (or three or four) overendowed adults consorting like a troop of deranged baboons is frightful to a child — at least until he gets used to it — and that's putting it mildly. Most of what's available online, some of which is pathological, makes jungle romance seem dignified.Filters help, but not much. Researchers found that unwanted porn exposure occurred despite the use of filtering and blocking software in more than half the homes with Internet access.Even the most innocent query produces porn. Googling "adult diapers" for a possible column about astronaut Lisa Marie Nowak, I found myself in the midst of diaper fetishists and paraphilic infantilists.We're not talking about incontinence here, but adults who like to dress and act like babies, including wearing diapers. Not all are sexual — babies don't have sex after all — but one thing leads to another on the Net. Where there are men in diapers, there are women to nurse them.Some of these folks, by the way, are offended by diaper jokes now circulating thanks to NASA's femme fatale. Here's a bet: We'll see hate-joke legislation to protect the certifiably fragile psyches of "adult babies," as they call themselves, before we see anything aimed at protecting real children from Internet porn.The multibillion-dollar mainstreaming of porn has distorted, among other things, our judgment. Other recent research shows that the more porn people watch, the lower their stand-ards for protecting children.Dr. Mary Ann Layden, co-director of the Sexual Trauma and Psychopathology Program at the University of Pennsylvania, tells of one study in which people were asked various questions before and after watching quantities of porn.One question was whether we should restrict children's access to XXX-rated material. Post-porn, the number of people answering "yes" was reduced by half.Assessing children's responses to porn is more difficult. You can't just herd kids into a room, subject them to pornography and then study their responses. But we can make reasonable assumptions based on adult research, a growing body of which suggests that porn is addictive and can be psychologically and emotionally damaging.Like any stimulant, the effects of porn diminish with use. More is needed to achieve the same result, the details of which we happily leave to the imagination.Research also indicates that porn consumption is related to dysfunctional relationships. Men are dissatisfied with real women who fall short of porn standards, while women feel inadequate and betrayed by their partners' attention to virtual mistresses.Children can't fare better. Never mind the visual impact of porn's genital inventories, but what are children to glean about grown-up relationships from watching men and women reduce each other to objects and orifices?Not much that will be useful to them as they try to navigate intimacy with a real human being someday.What a shame.And, if we had any sense, what a crime.