As the impressively depressing cover story “America the Obese” in the May issue of The Atlantic serves to remind us all, the weight-gain epidemic in the United States and the rest of the West is indeed widespread, deleterious, and unhealthy—which is why it is so frequently remarked on, and an object of such universal public concern. But while we’re on the subject of bad habits that can turn unwitting kids into unhappy adults, how about that other epidemic out there that is far more likely to make their future lives miserable than carrying those extra pounds ever will? That would be the emerging social phenomenon of what can appropriately be called “sexual obesity”: the widespread gorging on pornographic imagery that is also deleterious and unhealthy, though far less remarked on than that other epidemic—and nowhere near an object of universal public concern. That complacency may now be changing. The term sexual obesity comes from Mary Ann Layden, a psychiatrist who runs the Sexual Trauma and Psychopathology Program at the University of Pennsylvania. She sees the victims of Internet-pornography consumption in her practice, day in and day out. She also knows what most do not: Quietly, patiently, and irrefutably, an empirical record of the harms of sexual obesity is being assembled piecemeal via the combined efforts of psychologists, sociologists, addiction specialists, psychiatrists, and other authorities.

Young people who have been exposed to pornography are more likely to have multiple lifetime sexual partners, more likely to have had more than one sexual partner in the last three months, more likely to have used alcohol or other substances at their last sexual encounter, and—no surprise here—more likely to have scored higher on a “sexual permissiveness” test. They are also more likely to have tried risky forms of sex. They are also more likely to engage in forced sex and more likely to be sexual offenders.

As for the all-purpose cop-out that “all this shows is correlation,” it can be refuted as Dr. Johnson famously refuted the immaterialism of Bishop Berkeley—by kicking a stone. No one reasonable would doubt that there is a connection between watching sex acts and trying out what one sees—especially for adolescents, who rather famously and instantly ape the other influences on their lives, from fashion to drug use and more, as has also been copiously studied.

And this list is just one possible way of starting a conversation about the consequences of today’s novel sexual obesity. There is also the question of what the same material does to adults—about which another empirical record is also being amassed, and about which more will be said later in this essay. Pornography today, in short, is much like obesity was yesterday—a social problem increasing over time, with especially worrisome results among its youngest consumers, and one whose harms are only beginning to be studied with the seriousness they clearly deserve.

Parallels between the two epidemics are striking. Much like the more commonly understood obesity, the phenomenon of sexual obesity permeates the population—though unlike regular obesity, of course, pornography consumption is mostly (though not entirely) a male thing. At the same time, evidence also shows that sexual obesity does share with its counterpart this critical common denominator: It afflicts the subset of human beings who form the first generation immersed in this consumption, many of whom have never known a world without it—the young.

The data about the immersion of young Americans in pornography are startling and disturbing. One 2008 study focused on undergraduate and graduate students ages 18 to 26 across the country found that more than two-thirds of men—and one out of every ten women in the sample—viewed pornography more than once a month. Another study showed that first-year college students using sexually explicit material exhibited these troubling features: increased tolerance, resulting in a turn toward more bizarre and esoteric material; increased risk of body-image problems, especially among girls; and erroneous and exaggerated conceptions of how prevalent certain sexual behaviors, including risky and even dangerous behaviors, actually are.

In 2004, the National Center on Addiction and Substance Abuse at Columbia University reported that 65 percent of boys ages 16 and 17 reported having friends who regularly download Internet pornography—and, given that pornography is something people lie “down” about in surveys as well as in life, it seems safe to say those numbers underestimate today’s actual consumption, perhaps even significantly.

Finally, to connect the dots between “monkey see” and “monkey do,” a 2004 study in Pediatrics reported, in the words of its title, that “Watching sex on television predicts adolescent initiation of sexual behavior”—an ominous connection, given that Internet sex is vastly more realistic than anything available on television.

Even young people who don’t go looking for pornography are now routinely exposed—largely through incursions into popular media, including on phones (the “sexting” phenomenon), in video games, in pop music, and on television. A Kaiser Family Foundation study from 2005, for example, revealed that the number of sex scenes on television doubled between 1998 and 2005. The Foundation had previously noted that some 70 percent of youths aged 15 to 17 accidentaly came across pornography online. Even more startling, a 2006 Youth Internet Safety Survey of 1500 youths showed that one in seven reported unwanted sexual solicitation, and one in eleven reported being harassed online.

Yet another study confirms what many parents already will suspect: Most mothers and fathers know nothing about the online sexual experiences of their children.

But even this impressive array of data cannot answer a question almost as ubiquitous as pornography itself: So what? Why should people who are not part of that consumption even care about it? The varieties of the libertarian shrug extend even to those averse to it. Pornography indeed may be morally wrong, many of those people would also say (and of course major religions would agree); but, apart from the possible damage to the user’s soul, if you believe in such a thing, what really is the social harm of smut?

This lackadaisical attitude—this entrenched refusal to look seriously at what the computer screen has really wrought—is widespread. Religious people, among other people simply disgusted by the subject, understandably wish to speak in public of almost anything else. Closet users, and they are apparently legion, will probably already have stopped reading these words—or any others potentially critical of pornography—for reasons of their own; such complicity is probably the deepest font of omertá on the subject. And chronic users above all have their own fierce reasons for promoting the anything-goes-as-long-as-it’s-private patter—an interesting phenomenon about which more will be said further on.

And yet this hands-off approach to the matter of sexual obesity—this unwitting collusion of disparate interested parties masquerading as a social consensus—remains wrong from alpha to omega, as a new document signed by fifty experts from various fields and distilling just some of the recent empirical evidence, goes to show. Full disclosure: “The Social Costs of Pornography: A Statement of Findings and Recommendations,” just published by the Witherspoon Institute of New Jersey, was co-drafted by Mary Ann Layden and me. Unlike other pieces of writing, however, this compendium summons no authorial joy and is not the work of one or two but rather scores of people. Most of them academics and medical professionals, they represent a true rainbow coalition of the spectrum: left and right, feminism and conservatism, secularism, Judaism, Christianity, and Islam. It’s a collective attempt to render for the public good just some of the accumulating academic and therapeutic and other evidence of the harm and devastation now traceable to pornography abuse.

Bursting through the academically neutral language, the studies, the survey data, and the econometrics were the skin and bones of the very human stories that went into it all: the marriages lost or in tatters; the sexual problems among the addicted; the constant slide, on account of higher tolerance, into ever edgier circles of this hell; the children and teenagers lured into participating in various ways in this awful world in the effort to please romantic partners or exploitive adults. This report, in sum, like the conference that preceded it, answers definitively the libertarian question of “So what about pornography?” with a solid list of “Here’s what”—eight documented findings about the manifold risks of warping the sexual template with pornographic imagery.

Reading work after work by the experts for the purpose of condensing and putting it into laymen’s terms felt at times like what might be called a labor of hate—hate for what pornography addiction does, for all corrupters and would-be corrupters of the innocent, and for the mistaken libertarian nonchalance that enables such continuing corruption.

Of all the untruths about this subject today that are belied by the factual record, I would like to focus here on just three of the most influential and reckless.

Pornography use is a private matter. Perhaps the queen bee of lies about pornography, this is also the easiest to take down. For while consumption of the substance may be private (or not, as airline travelers and library patrons and others in the public square have lately been learning), the fallout from some of that consumption is anything but.

Consider just a few examples from recent studies on people younger than eighteen. Adolescent users of pornography are more likely to intend to have sex and to engage in more frequent sexual activity. They are more likely to test positive for Chlamydia. Three separate studies have found among adolescents a strong correlation between pornography consumption and engaging in various sexual activities.

The exceedingly well-documented social costs of adolescent sexual activity, alongside the health costs now accumulating, alone torpedo the refrain that Internet pornography use today is “private.” Now consider a few more findings concerning adults rather than kids. At a November 2003 meeting of the American Academy of Matrimonial Lawyers (comprising the nation’s top 1600 divorce and matrimonial-law attorneys), 62 percent of the 350 attendees said the Internet had played a role in divorces during the last year. In especially germane research not yet published, economists Kirk Doran and Joseph Price are examining data from the General Social Survey (GSS) to assess the negative impact of pornography on other aspects of marriage. They report that, among individuals who have ever been married, those who say they’ve seen an X-rated movie in the last year are 25 percent more likely to be divorced and 13 percent less likely to identify themselves as “very happy” with life in general.

Divorce, as everyone knows by now, is associated with a variety of adverse financial and other outcomes as well as with problems for children and adolescents affected by it. Here too, private behavior is clearly exacting public costs.

Yet with all due respect to the social science, not everyone needs it to know that pornography is more than just a private thing. Imagine your teenage daughter walking down the beach. Half the men on it have been watching sex on the Internet within the last few days, and half have not. Which ones do you want watching her? How can their “private” behavior possibly be said to be confined to home, when their same eyes with which they view it travel along with them everywhere else?

Pornography use is a guy thing. It only bothers women. In fact, some of the saddest and most riveting testimony on this topic concerns exactly this: the harm that pornography consumption can do to men immersed in it.

Consider the insights of Pamela Paul, a reporter for Time magazine, who interviewed in depth more than 100 heterosexual users of pornography, 80 percent of them men, for her 2005 book Pornified: How Pornography Is Transforming Our Lives, Our Relationships, and Our Families. This book—the best yet written in laymen’s terms about the impact of Internet pornography on users themselves—is remarkable for several reasons. Just one is the unforgettably sad portrait that emerges, sometimes unwittingly, from habitual users themselves. “Countless men,” she summarizes from the interviews, “have described to me how, while using pornography, they have lost the ability to relate to or be close to women. They have trouble being turned on by ‘real’ women, and their sex lives with their girlfriends or wives collapse.”

The same point has been echoed by medical authorities including Norman Doidge, a doctor specializing in neuropsychiatry and author of The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science. Treating men in the early to mid-1990s for their pornography habits, he found it a common refrain that many were no longer able to have intercourse with their own wives. “Pornographers,” he concludes, “promise healthy pleasure and relief from sexual tension, but what they often deliver is an addiction, tolerance, and an eventual decrease in pleasure. Paradoxically, the male patients I worked with often craved pornography but didn’t like it.”

At least some of the shame and disgust that users sometimes report to therapists may be due to another phenomenon well documented about chronic pornography use: habituation and tolerance. Just as heavy drinkers and drug users over time require higher doses of substances to achieve the same effect, so apparently do some chronic users of pornography come to require harder-core and edgier material. From another of Pamela Paul’s descriptions: “Men . . . told me that they found themselves wasting countless hours looking at pornography on their televisions and DVD players, and especially online. They looked at things they would once have considered appalling—bestiality, group sex, hard-core S&M, genital torture, child pornography.”

This same descent into the particular pit of knowing that one is doing something wrong, and still being unable to stop oneself, echoes through other accounts by clinicians of what they hear from some patients. In a widely read article in the London Spectator in 2003, British writer Sean Thomas courageously catalogued his own such descent, including into terrain that will not be described here. As he concluded, Internet pornography “revealed to me that I had an unquantifiable variety of sexual fantasies and quirks and that the process of satisfying these desires online only led to more interest.”

But self-loathing is hardly limited to the most extreme cases. Recently, National Review Online ran an anonymous and widely discussed essay called “Getting Serious About Pornography.” Its author, a mother of five, detailed and deplored pornography’s role as she saw it in the destruction of her marriage. The result was an outpouring of impassioned e-mail—including from some people exploring their own use of pornography and its impact on their own lives. As one military man put it with unusual candor in a particularly poignant (also anonymous) e-mail to the editor:

I absolutely agree it is damaging. It damages my respect for my wife, and she has done nothing to deserve that damage. It damages my self-esteem and respect for myself, because I know it is not helpful to our life, to our marriage, to our love. . . . It reduces my satisfaction in a wonderful woman. It makes me yearn for things that I should not want. It is disruptive to my inner peace. I don’t like myself when I’m looking at porn. I don’t like the way I feel about myself when I’m looking at porn . . . . But I can only do without it about six months. . . . It has been an endless cycle.

Or as Roger Scruton put it memorably at the Witherspoon conference, summarizing the philosophical aspect of this particular form of sadness that this new form of obesity can bring: “This, it seems to me, is the real risk attached to pornography. Those who become addicted to this risk-free form of sex run a risk of another and greater kind. They risk the loss of love, in a world where only love brings happiness.”

It’s only pictures of consenting adults. Unless it is computer simulated, pornography is never only about pictures. Every single person on the screen is somebody’s sister, cousin, son, niece, or mother; every one of them stands in a human relation to the world.

The notion for starters that those in the “industry” itself are not being harmed by what they do cannot survive even the briefest reading of testimonials to the contrary by those who have turned their backs on it, among them Playboy bunnies (including Izabella St. James, author of Bunny Tales). It is a world rife with everything one would want any genuinely loved one to avoid like the plague: drugs, exploitation, physical harm, AIDS.

Nor can that defense survive the extremely troubling—or what ought to be extremely troubling—connections between pornography and prostitution. New York Times columnist Nicholas Kristof has notably taken the lead in investigating and throwing light on the sordid phenomenon of “sex trafficking,” both here and abroad. Yet trafficking, as the Department of Justice and the National Center for Missing and Exploited Children have both noted, is often associated with pornography—for example, via cameras and film equipment found when trafficking circles are broken up. Plainly, the reality of the human beings behind many of those images on the Internet is poorer, dirtier, druggier—and younger—than pious appeals to “consenting adults” can withstand. Is this world really what the libertarian defenders of pornography want to subsidize?

Once again, who even needs all that social science? Perhaps the most telling response to the “pictures” defense is rhetorical. Ask even the most committed user whether he wants his own daughter or son in that line of work—and then ask why it’s all right to have other people’s daughters and sons making it instead.

Several experts have also noted one more interesting phenomenon that most people who have ever written on this thankless subject will verify: Telling the truth about pornography is practically guaranteed to elicit malice and venom unique in their potency from its defenders.

This aspect of sexual obesity too, I believe, tells us something of note. Blogging recently about the subject on National Review Online, for example, Kathryn Jean Lopez remarked in public about the quality of the torrent of emotional e-mails her comments provoked. Many of them, she reported, were “terrifying.” Cathy Ruse, who worked on the issue of pornography during the mid-1990s for the National Law Center for Children and Families and again later for the Family Research Council, reports similarly: “I have been involved in various public policy debates in the United States for twenty years and I have never encountered anything like the pornography debates. . . . I have never experienced attacks that were so abusive and personal, including angry ranting messages on my home telephone and horrible e-mails.”

Such unique vituperation, which has so far gone unremarked in any public discussion of pornography despite the fact that it is commonplace, demands inspection in its own right. In fact, it may be the surest proof altogether of just how addictive Internet pornography can be. Although academic experts may continue to battle over exactly what is meant by “addiction,” surely the tremendously defensive response in the public square by itself settles the question to any reasonable person’s satisfaction. What does it tell us that, when faced with any attempt to make the case that this substance should be harder to get than it is, some reliable subset of defenders can be counted on to respond more like animals than like people? If such is not the very definition of addiction, what is?

All of which goes to show that there is nothing alarmist whatsoever in arguing that we ought to be alarmed about the first generation raised on Internet pornography. In speaking on college campuses about other issues lately, I have been struck by how many students—usually, though not only, girls—have come up afterward and confided their view that pornography use is the number-one factor warping relations between the sexes these days. I have also heard at least a few boys confide that it’s hard to find girls on campus who have not themselves been drawn in to some form of the pornographic subculture—via “sexting,” say, or in the effort to please previous boyfriends, or in the deliberately provocative pictures of themselves on Facebook and elsewhere.

What, if anything, can be done about this other obesity epidemic? For starters, we could use a campaign that might promise to do to pornography what was ultimately done to tobacco—a restigmatization based on the evolving record of fact. What’s needed is nothing less than the kind of leadership that turned smoking, in the course of a single generation, from cool to uncool—one eventually summoning support high and low, ranging from celebrities, high-school teachers and principals, counselors, former users, and anyone else who knows they belong in the coalition of the willing on this wretched issue.

Perhaps when the First Lady concludes her campaign against “regular” obesity, she or someone else of similar public stature can spare time for this other epidemic, too. After all, uninviting though these dirty waters may be, the reward for tackling this epidemic could be profound. For amid the squalor, the unhappiness, and the rest of the bad news about sexual obesity, the bad news isn’t the only news there is—not at all.

“Where sin abounded,” as Paul’s Letter to the Romans has it, “grace did much more abound.” The empirical record shows that too, though it may not yet be an issue of academic study. After all, just look at the tremendous effort that goes into attempts to break the habit. Look at the energy fueling all those attempts to repair the damage done—the turns to counseling, the therapists, priests, pastors, and others working in these awful trenches to help the addicted get their real lives back. Look at the technological ingenuity too—the new software, the filters, the countercultural and uphill efforts here and there to thwart pornography’s public crawl.

To survey that multifaceted record of struggle, fledgling but growing by the day, against the also rapidly growing empirical record of the beast’s harms, is to grasp a truth about this new obesity beyond the ridicule of the jaded or the vituperative recriminations of those still in the pit. It is to see redemption. It is to spy hope in a place where desperate people need it most—and plenty of it, too.

Mary Eberstadt is a contributing writer to First Things, a research fellow at the Hoover Institution, and author of The Loser Letters: A Comic Tale of Life, Death, and Atheism.