The number of men paying women for sex has nearly doubled in a decade, UK research suggests.
Twice as many men said they had paid for sex
Surveys of 11,000 British adults in 1990 and 2000 found the rate increased from one in 20 to nearly one in 10 men.
Rising divorce rates, sex tourism and increasing availability of commercial sex are blamed by the Sexually Transmitted Infections journal.
It warns men's lifestyles put them at risk of catching sex diseases, yet few are getting checked in clinics.
Only a fifth had visited a sexual health clinic and even fewer had been tested for HIV.
The findings come as experts call for a radical rethink of sexual health services to tackle rising rates of sex diseases.
In the UK there has been a resurgence of sexually transmitted infections (STIs) such as chlamydia, gonorrhoea and HIV.
More than 58,000 are now living with HIV in the UK and 104,155 new cases of chlamydia were reported in 2004, latest figures show.
The study authors, from Imperial and University College London, the London School of Hygiene and Tropical Medicine and the National Centre for Social Research, do not believe the rise in paying for sex is the prime cause for this, but warned it could be a contributing factor.
While women who sell sex in the UK have been targeted by campaigns to promote safer sex and uptake of sexual health checks, on the whole men who pay for sex have not, they said.
And their work shows these men often have other risk factors for STIs including higher numbers of partners in general.
More than a third of the men in the study had 10 or more sexual partners during the previous five years.
Meeting new sexual partners while abroad, including in countries with higher rates of STIs than the UK also increased risk.
The men most likely to pay for sex were single, living in London and aged between 25 and 34.
There was no link with ethnicity or social class, however.
Lead author Dr Helen Ward said there were many reasons why more men were paying for sex.
"There has been a more liberal attitude towards commercial sex and increasing commercialisation of sex. Lads magazines are bombarded with images.
"There are more men with money and more women looking for this type of work."
She said many men were meeting new partners abroad, on stag nights for example, and the internet and cheaper international travel meant people had more opportunities to buy and sell sex.
"It does not seem to be exceptional for groups of men to go away with each other for the weekend and have commercial sex.
"My concern is that if people are going abroad where there might be less safe sex, they really ought to be thinking about the possible risks.
"Men who pay for sex should be the target of health promotion campaigns and screening initiatives," she said.
She said such programmes could be targeted at young male travellers and groups of men going on holiday or stag party trips, but that it might be better to target men in general, starting with school based sex education and mass media campaigns.
Peter Baker, of the Men's Health Forum, agreed it was important to target all young men because those most at risk were the least likely to use health services.
He added: "Many people will be surprised by the relatively large numbers of men who are willing to pay for sex.
"But it's not so surprising in the context of social trends - women are increasingly sexualised in the media, sex phone lines are routinely advertised in the back of magazines and phone boxes...and divorce and separations are on the rise."
A new report by the NHS Confederation and the Terrence Higgins Trust says the way NHS sexual health services are currently run must be comprehensively overhauled because existing services cannot cope with demand.
It says there should be a shift towards community-based services focusing on both contraception and STIs, including HIV.
Jo Webber, of the NHS Confederation, said: "A fresh approach is needed."