The new sex tourist destination.

It took a bit of time for Mark, a 65-year-old retiree from London, to understand why so many middle-aged white men were hanging out alone in the sad-looking bar of his hotel in Vientiane, Laos, when he visited in 2013. Then he saw all the local young women loitering nearby. And that’s when Mark realized that, unlike him, those dudes hadn’t come to Laos for its stunning 16th-century temples or spectacular waterfalls.

Tourism is taking a turn for the torrid in Laos — and the once isolated country has a host of rivals that stretches all the way to Myanmar and Bangladesh. While none of these countries are exactly contending for the dubious mantle of sex tourism capital, they’re all finding opportunity, of sorts, as Thailand’s government cracks down on its own world-famous sex industry. Lured by tourism’s economic promise but lacking the wherewithal to prevent sex trafficking and other abuses, many of these countries are in a difficult spot, experts say. Myanmar, for instance, recently denied entry to several known transnational child sex offenders, but scores of others get through easily.

“For some sex offenders, finding new destinations and unsuspecting locals is part of the appeal,” says Karen Flanagan, manager of the child-protection unit at Save the Children. Indeed, one need spend only a few minutes in the seedier quarters of the Internet to see that the industry is charting new territory. “Burma is the new flavor of the month,” writes a man who calls himself Alejandro. “It seems everyone is wanting a slice of the [new] cake,” agrees Pak2F. “I think Lao women are so fine!” says Sam.

Even when it’s not on the books, sex work can become a vital part of the economy.

The backdrop to this is tourism’s rapid growth in these countries. If part of the sex tourism thrill is “finding new destinations,” these Southeast Asian countries, once closed to the world, fit the bill. Only a few years ago, hardly anyone could get a tourist visa to Myanmar; this year, the country expects to welcome more than 3 million tourists. In Communist Laos, foreign visitors already generate 12 percent of the gross domestic product, according to the World Travel and Tourism Council, and though Bangladesh has never been as isolated as either of those countries, it is nowadays investing heavily in tourism: Its contribution to the economy has quadrupled since 2012.

And make no mistake: Even when it’s not on the books, sex work can become a vital part of the economy. In the mid-1990s, well before its peak, sex tourism contributed as much as $27 billion to Thailand’s GDP, according to the International Labor Organization. Not all of that went to the prostitutes, of course; it also benefited hotels, corrupt cops, restaurants, tourist agencies, beer gardens, saunas, cabarets and, of course, health clinics. (In Bangkok, some 19 percent of freelance sex workers hadHIV in 2007.) Today, some of the new sex tourists are well aware of their role in the economy. One young American, who visited the Philippines and spent about $50 a night to be with a girl, made himself sound like an agent of social good, since “the sex is consensual and there is no abuse, human trafficking or drugs involved.”

But in many of the new destinations, human trafficking, drugs and abuse are often involved — as are child exploitation and sexually transmitted diseases. Thailand’s crackdown began mostly out of concern for public health, after all, and only when STDs reached epic proportions. Tourism today presents new challenges. Even supposedly do-gooder ventures, like voluntourism and orphanage tourism, “present a new risk of sexual exploitation for vulnerable children,” says Dorine van der Keur, an expert on child sex abuse and tourism at the nonprofit ECPAT International. Meanwhile, the Internet is making it easier to bypass the police. On a site filled with pictures of supposed Bangladeshi prostitutes, “Jono” asks, “How much for street pros in Dhaka 2015?” and an entrepreneurial local under the name “Playboy Dark spider” promptly offers to arrange an escort for $60.

The governments of these developing countries have little ability to track down men like Jono. Tourism ministries did not respond to requests for comment, but experts say enforcing laws against prostitution has been difficult enough; busting up trafficking networks would be a dream. So how can these up-and-coming destinations reap tourism’s benefits without suffering the costs, human and otherwise, of exploitation? Some believe the best option would not be a Thai-style crackdown but to legalize the sex trade and then strictly monitor it, as do Amsterdam and Singapore. Keeping the sex trade in the dark allows it to flourish, according to Phil Robertson, deputy director of Human Rights Watch’s Asia division. And with the sex trade in the dark, “governments in the region are only ensuring that it becomes more difficult for sex workers to assert their rights,” he adds.

Yet even legalization doesn’t tackle the root of the problem: demand. That’s why many charities insist prevention is the only long-term solution. And in the eyes of Flanagan and Save the Children, salvation will come only by teaching men respect for women around the world. “Otherwise, the problem will just keep jumping from country to country,” Flanagan says.