The Brazilian city of Salvador is this week hosting the first World Tourism Forum, and one of the main items on the agenda is how to combat the menace of child sex tourism. The BBC's Steve Kingstone reports from Recife, one of the centres of the Brazilian sex tourism industry.
Brazil's sun-drenched beaches are a lure for tourists
The UN estimates that two million young people under the age of 18 are involved in prostitution.
Traditionally the trade has been associated with Asia. But in recent years, Brazil has become an increasingly popular destination.
There's a paradise quality to Recife on the country's north-east coast.
Not the paradise of desert islands and solitude but a more earthly variety, with vibrant beaches and beautiful people.
The latter is the attraction for a growing number of foreign tourists who come to Brazil looking for sex, and in many cases they are willing to pay for it.
There is a growing demand, mostly from Germans, Italians and other Europeans, says Sessie Prostrello of campaign group Mulia Vida.
They come here not for the culture and beaches, she says, but for sex, often with minors.
The age of consent in Brazil is 18, but many of those at work here are much younger.
As I drive along the main road a block back from the beach at 1am, it is lined with young women flagging down drivers for sex.
A car stops just up ahead of me. Some of these girls are shockingly young - perhaps 12 or 13 years old.
Child sex has boomed in Brazil as Asia cracks down on sex tourism
In a bar where foreign men meet Brazilians, I was approached by Paula who said she was 19 but seemed younger. She was with her mother.
Paula explained that she was looking for a man who could give her a better life in Europe. She said her two sisters were already in Germany.
Later, a Brazilian BBC colleague spoke to Paula's mother, who said Paula could come to my hotel that night - it was for me to name the price.
A mother prostituting her own daughter may seem shocking, but in the end it comes down to basic economics.
Brazil has a supply of young girls desperate to escape poverty, and the demand from foreign men is rising all the time.
Recife's secretary for tourism, Romeo Batista, says the long-term antidote to the sex trade lies in better social policies so that Brazilian girls have less need for foreign men and money.
But on the question of short-term solutions, he was somewhat defensive.
"Prostitutes exist everywhere - look at Paris for example.
"Here they just happen to work in highly visible areas, and it's not just a question of getting them off the streets.
"You have to deter their clients, which is why we've installed cameras which also help reduce violence."
Campaigners say the rise of sex tourism in Brazil is partly a consequence of its relative decline elsewhere.
As the authorities have become stricter in east Asia, for example, some of the trade has shifted to Latin America.
But Brazil is also a victim of its own marketing.
In travel brochures the country is portrayed as a land of samba and sensuality. Posters often show half-naked women.
Sergio Folgill is the Brazilian president of this week's World Tourism Forum.
Brazil has become known for beautiful people and big parties
He says sex tourism is perhaps inevitable, but it is up to the authorities not to encourage it through marketing.
"Look, sex is part of our life. It can be a very healthy part of our life," he says.
"The question is the use of sex to attract tourism. When it tends to be an attraction for new tourists to come, here is where we have a problem."
Selling Brazil as a sexy country but without encouraging sex tourism is a delicate balance which has perhaps yet to be struck.