Networks of businessmen, government officials and politicians are behind the country's booming illegal sex industry, Rak Prathet Thai Party leader Chuwit Kamolvisit alleged yesterday.

"The sex industry earns more than Bt200 billion a year. It's [equivalent to] almost 10 per cent of the country's national budget," said Chuwit, a former massageparlour tycoon.

Speaking at a press conference, the colourful politician said he would go to the US Embassy today to provide information on human trafficking.

"Prime Minister Yingluck Shinawatra should take action against human trafficking. Up to one million Thai women work in the flesh trade. Of them, about 100,000 are younger than 18 years old," Chuwit said.

He handed out CDs containing video clips showing how procurers negotiate prices with potential customers, as well as scantily clad women waiting for customers in front of karaoke parlours and row houses.

According to Chuwit, many prostitutes work the streets, while many others are based at seemingly conventional massage parlours, beer bars, spas and resorts.

"There are prostitutes working on Phetchaburi Road. Their bases are very close to the Pheu Thai Party's headquarters," Chuwit said.

He added that gambling dens were still operating on Soi Kingpetch 4 and Soi Kingpetch 6 on Saturday nights.

Meanwhile, Khon Kaen University's Centre for Research and Training on Gender and Women's Health released the findings of a survey of women who had been pregnant as teenagers.

The survey covered 3,114 women who had been pregnant before they reached 20 years old.

Conducted with financial support from the Social Development and Human Security Ministry, the survey found the youngest to become pregnant was just 11. Of the respondents, 62.9 per cent had older boyfriends and 33.9 per cent had unprotected sex when they had sex for the first time.

"Of those questioned, 70 per cent said the pregnancies were unplanned and about 70.3 per cent had to leave their schools because of the pregnancies," Prof Dr Siriporn Jirawatkul of the centre said.

Sirikiat Liangkorbkij, who heads the Thai Health Promotion Foundation's Health Risk Control II Section, said sex education lessons should be integrated into the curriculum for secondary schools as a measure to prevent unwanted pregnancies.

On St Valentine's Day this year, 19 couples will register their marriages at the Giant Royal Flora Wheel and receive gold marriage certificates.

Uppatham Nisitsukjarern, who heads the Project Management Office of the International Horticultural Exposition Ratchaphruek 2011, said the couples, chosen from a campaign about love, would not have to pay any fee.