Arthur is an alleged john, a man who patronizes prostitutes. After his arrest on September 5, 2008, a photograph of this 41-year-old appeared on the Web site of the Chicago Police Department. Arthur (not his real name) was far from the only person so branded on this Internet portal. Samuel, 59, and José, 34 (whose names were also changed to protect their privacy), were on this online pillory for a month after their September 5 arrests.

The apprehensions of Arthur, Samuel, José and many others represent the huge demand among males for prostitutes. In the U.S., police officers detained about 75,000 people in 2008 for prostitution-related crimes, according to the Federal Bureau of Investigation. Experts believe that about 10 percent of these arrests are of the sex patrons, almost all of whom are men.

Overall, an estimated 16 percent of men pay for sex in the U.S., according to a 2005 report by social work professor Sven-Axel Månsson of Malmö University in Sweden. And a study published in 2000 of 998 street prostitutes and 83 call girls in Los Angeles led by sociologist Janet Lever of California State University, Los Angeles, suggests that 28 percent of men who patronize prostitutes and nearly half of those who employ call girls buy sex regularly, with the rest being occasional customers.

The proportion of patrons seems to vary considerably by country and by study. Månsson reported that 14 percent of Dutch men have bought sex as compared with nearly 40 percent of men in Spain. (Prostitution is legal in both countries.)

And according to HYDRA, a Berlin-based organization that provides legal advice and other aid to prostitutes, up to three quarters of men in Germany, which also has legalized prostitution, have paid for sexual services. Meanwhile other estimates for Germany put the proportion far lower, at about one fifth. In Thailand, where prostitution is illegal but socially accepted, one study suggested that a whopping 95 percent of men have slept with a prostitute.

Whatever the numbers, the behavior is prevalent enough that psychologists cannot easily write it off as pathological. Rather men's motives for buying sex are hotly contested among researchers. Some believe the practice serves as a salve for common psychological afflictions, such as an unfulfilled appetite for sex, love or romance. Others paint a dimmer portrait of johns, believing they are typically driven by chauvinistic motives, such as a desire to dominate and control women. A similar debate rages among experts about the morality of prostitution itself [see box on page 63].

Of course, the simplest explanation for men buying sex is that they like it. After all, people are generally willing to pay for activities they enjoy as much as they do sex. On the other hand, a man can usually get sex for free in the context of an ordinary intimate relationship. So why pay good money for it, especially given the social and health risks of having sex with a prostitute? Are all johns so unappealing that they cannot get sex any other way?

Most researchers do not think so. Johns come from all socioeconomic classes, according to culture researcher Sabine Grenz of the University of Gothenburg in Sweden. They may be stockbrokers, truck drivers, teachers, priests or law-enforcement officials. Many are married with children. “There are no social characteristics that basically distinguish johns from other men,” says Grenz, who published her interviews with a large number of johns in a 2005 book.

Nor are these men defined by obvious personality problems. In a survey published in 1994 psychologist Dieter Kleiber of the Free University of Berlin had some 600 johns fill out the Freiburg Personality Inventory and found no particular abnormalities. The only correlations he found applied to risk taking and unprotected sex. For example, the men who demanded sex without condoms tended to score higher on aggression, and married and well-to-do customers practiced unprotected sex more frequently than others did. “The more secure and orderly a man's life is, the more he believes in his own invulnerability,” Kleiber concludes.

The research underscores the diversity of the men who pay for sex. Accordingly, these individuals seek prostitutes for varied reasons. Some of them may indeed be driven purely by sexual impulse. In a study of johns sponsored by the Rosa Luxemburg Foundation, sociologist Udo Gerheim of the University of Bremen, Germany, found that many of these men are either sexually frustrated (because they are not getting satisfying sex elsewhere) or hedonists who want to live out their erotic fantasies in a red-light setting.

Representatives of HYDRA similarly say that men go to prostitutes to appease a sexual appetite. Many men feel freer to experiment within the context of commercial sex than with their wives or girlfriends, enabling them to expand their sexual range and to experience greater sexual fulfillment.

Yet some researchers have identified emotional and psychological motivations among the men who purchase sex. Gerheim spotted a type of romantic john who imagines that he is having a genuine relationship with a prostitute based on mutual trust. Kleiber also saw a romantic streak in many of his interviewees. These men, Kleiber explains, seem to be pursuing the ideal of love in a fee-for-service setting.

When Kleiber and his colleagues asked johns to characterize the prostitutes they patronize, most rated them as “charming” and “open.” Some also said these women were “intelligent” and “witty.” Many of the men painted a picture of a perfect woman whom they would like to get to know better. A few even penned statements such as “I can easily imagine the prostitute to whom I go as my wife.” “These men have emotionally charged relationships with prostitutes,” Kleiber says. They portray these relationships as intimate despite their commercial nature and limited scope, he adds.

The behavior of male customers during their encounters with prostitutes also may suggest that they seek a social connection outside of coitus. From her interviews with Los Angeles prostitutes, Lever learned that purchasers of sex often ask indiscreet questions such as “Where do you come from?” or “Is Lara your real name?” before and after the act.

As if to continue their “relationship,” many if not most johns prefer to go back to the same prostitute over and over again. According to Kleiber's study, more than two thirds of devotees used the services of a particular prostitute more than 50 times. One in four had sex with the same prostitute more than 100 times.

But why would a man turn to a prostitute—as opposed to a girlfriend, wife or other consensual female lover—to satisfy his need for a social bond? One reason may be that real relationships with women are risky and complicated, features that men do not always want and cannot always handle. Prostitutes are far less exacting than girlfriends and wives and may even be soothing to the psyche.

That is, an ordinary female date might reject a man or happen to be tired, distant or not in the mood. In contrast, sex workers generally accept their customers unconditionally and offer intimacy on demand, whatever their true feelings, says gender researcher Gunda Schumann, who co-authored a 1980 book on the psychology of prostitution. “They offer the men emotional involvement, psychic stability and empathy,” she observes. In this view, ordinary men buy sex to deal with their psychological insecurities as well as their sexual needs.

The idea that sex with a prostitute can be therapeutic dates back thousands of years. In the Epic of Gilgamesh, a poem from ancient Mesopotamia, Enkidu—a friend of the king who is half wild—is civilized by having sex with a whore. The tale portrays the prostitute as sacred because she sacrifices herself to the man to cleanse him of destructive inner forces.

Other researchers disagree that prostitutes serve as a balm for the woes of essentially normal men. Sociologist Julia O'Connell Davidson of the University of Nottingham in England characterizes johns as necrophiliacs who commit their acts on socially “dead” women. These are men, she says, whose sexual desire is switched on by not having to care about the prostitute as a human being—the opposite of the intimacy hypothesis.

“What turns the john on is the woman's powerlessness,” O'Connell Davidson concludes. Sex with a prostitute, she says, is more about seeking revenge on women or exerting control over them than about a quest for intimacy and romance.

In a speech he gave to the European Parliament in 2006, Månsson pointed out that johns frequently speak about sex “as a consumer product rather than an expression of intimate relations.” One man, he reported, compared sex with a prostitute to “going to McDonald's.” Indeed, on the Internet, where a person can remain relatively anonymous, many johns refer to women as “material,” Gerheim notes, and may also describe misogynistic submission fantasies.

Some sex purchasers may even have a social agenda to go along with their personal predilections. For many of them, Månsson opines, a prostitute's bed represents the last bastion of antifeminism. Only there can men reestablish the traditional male dominance over women.

Catering to such men, brothels in countries where these institutions are legal hawk women like merchandise on their Web sites. Meanwhile nudist clubs in nations such as Germany attract customers with “all-inclusive” deals: for a fixed price (often less than $100), men can have sex with any of the women present. Some clubs even offer happy-hour specials.

Månsson believes that johns are usually psychologically disturbed and in need of counseling and treatment. Many Swedish johns similarly view their sexual behavior as “out of control” or “psychologically toxic,” a self-characterization certain scientists reject. In the opinion of these dissenters, johns in the U.S. and other countries that ban prostitution are unjustly criminalized and labeled mentally unstable.

However toxic the activity might be to the men, the women often end up more seriously wounded by it. At the very least, prostitutes suffer psychologically from trying to wall off their own emotions so that they can sell intimacy as a commodity. In addition, they often suffer from physical abuse at the hands of their customers. The 2006 annual report of KARO, an organization trying to thwart prostitution in the region dividing Germany and the Czech Republic, noted many incidents of brutality related to the selling of sex. Prostitutes in the U.S. are also subject to high levels of violence.

Prostitution is not a profession women pursue because they like the work. As stated on the KARO Web site: “Very few women have ever said that they voluntarily became prostitutes.” Poverty, drug addiction or fear of violence from pimps often pushes women into the sex trade.

Thus, many experts argue that the female sex workers are not the real drivers of prostitution. Instead the business survives because of demand from the legions of males who have problems in their relationships with women. This rationale lies behind the law in Sweden that came into force in 1999 under which selling sex is legal but buying sex is not. The same notion also propels a growing crop of workshops and classes in the U.S. that are aimed at discouraging offending males from repeating an act that many consider a crime against women.