Angeles City, 80km north of the capital of the Philippines, Manila, is known for its red-light district. From 1903 until 1991, the Clark Air Base - once the largest US Air Force facility outside the United States - was located 5km west of the city.

Many brothels and girlie bars opened to cater to the American service personnel stationed at Clark, turning the city into one of Asia's most popular sex-tourism destinations - a status it has retained long after the GIs packed up and shipped out.

Today, about 12,000 women are working in the bars that line Fields Avenue, in the city's red-light district. Unlike in Thailand, where customers pay by the hour or night, the international clientele of Angeles City tend to seek a "girlfriend experience", which can last for months.

Each year, thousands of children are born from such paid relationships; in this Catholic country, abortion is a criminal offence. The men often abandon their offspring, and many of these children grow up searching for an identity with no knowledge of their father's name or his background.

Exact figures are hard to come by, but in 1992, the number of American-fathered Filipinos born to sex workers in Angeles City numbered 10,000, according to NGO Preda Foundation. It is estimated that more than 250,000 children have been sired across the Philippines by American soldiers since 1898, when the US colonised the country.

Journalist Jarius Bondoc, quoting a study prepared for the Philippine Amerasian Research Centre at the Systems Plus College Foundation in Angeles City, says 200,000 children have been born to Japanese fathers in the country - mostly during the 1970s and 80s, when sex tours to the Philippines were openly advertised in Japan - and 30,000 to Korean fathers, mostly students who come to study English.