A small shelter and school for Korean-Filipino children, whose mothers are poor and whose fathers are nowhere to be found, highlights one side effect of a rise in South Korean visitors to the Philippines.

QUEZON CITY, Philippines— Son Bum-sik takes credit for coining the term Kopino. He uses it to describe a person of mixed Korean and Filipino ethnicity. In 2006, he opened a small shelter and school for such children whose mothers can't afford to take care of them and whose fathers are nowhere to be found.

As a South Korean, "I feel responsible," says Mr. Son, 50 years old. "Some Korean men take no responsibility if they get their Filipino girlfriends pregnant."

Since Mr. Son founded the Kopino Children's Association, around 200 children have lived with him and his Filipino wife Normi. The couple has two Kopino children of their own.

The Sons "are like our second parents," says 20-year-old Dawn Deladia, one of 16 current residents at his shelter. The university student, whose mother works overseas, says she and her younger brother have no contact with their South Korean father. "I don't know anything about my father, just his name."

Shelter residents Dawn and John Deladia have a Filipino mother and have never met their Korean father. Malte E. Kollenberg for The Wall Street Journal

Kopino children are part of the Philippines' diverse melting pot of ethnicities. After centuries of colonization, many Filipinos claim Spanish and American genealogy. And like the Kopino Children's Association and other similar charities, there are also support groups for Filipinos separated from their Japanese fathers.

Mr. Son says many Korean men leave behind their children because of difficulties obtaining marriage visas for their Filipino spouses. "Some do send back money for support," he says. But he says other Koreans who father children in the Philippines are students who come to study English on the cheap, businessmen or tourists, many with wives and families back home.

Tourism statistics from the Philippines' government show South Koreans account for nearly one-fourth of last year's 4.7 million foreign visitors, outnumbering all other nationalities. That is nearly a near doubling over the past five years.

Other child-welfare proponents say the rise of Kopino births is directly related to the growth of the South Korean community in the Philippines.

There are no official statistics on how many children of Korean heritage have been born in the Philippines. But the Seoul-based branch of advocacy group End Child Prostitution, Child Pornography and Trafficking of Children for Sexual Purposes, or Ecpat, estimates the number has soared to 30,000 from 10,000 in just the past few years. Lee Hyeon-sook, the organization's director, bases those figures on reports from children's aid agencies in the Philippines.

Ms. Lee says Korean men coming to the Philippines in search of temporary liaisons or prostitutes is a main factor.

"Koreans have long complained about being victims or sexually exploited by Japan and the U.S. Since becoming a developed economy, Korean men go to countries like the Philippines and have become perpetrators themselves," Ms. Lee claims.

Left-behind Kopino children are a cause of embarrassment and a "loss of face" for South Korea, says Jasmine Lee, a South Korean lawmaker who is originally from the Philippines. Abandoning children contradicts the notion of Korea having "a very family-oriented culture," she says.

South Korea's Ministry of Foreign Affairs is aware of the rise of the Kopino population in the Philippines, according to a ministry official. Under the law, Koreans can be imprisoned and have their passports revoked for "damaging the honor" of the nation, the official said. That includes being caught soliciting sex overseas. The official added that the government-funded aid group Korean International Cooperation Agency, or Koica, is providing assistance to Kopino children in parts of the Philippines.

Spokesmen for the Philippines' departments of health and foreign affairs said the issue of Filipino-Korean children isn't one their departments track.

Mr. Son says he doesn't want to put the blame solely on the absentee Korean fathers or the Filipino mothers of the Kopinos. "Every situation is different," he says. "I'm not telling the children they need to track down their fathers someday. They need to study and be able to earn a living."

South Korean Son Bum-sik opened the shelter for Filipino-Korean children in 2006 in Quezon City. Malte E. Kollenberg for The Wall Street Journal

Mr. Son says he is more concerned that Kopinos are getting a bad name in his ethnically homogenous homeland. He fears these children aren't accepted because they often are the result of affairs with relatively poor Southeast Asian women.

"There is no reason why these children should face discrimination" just because they are of mixed ethnicity, Mr. Son says.

It isn't clear what rights the Kopinos have in South Korea. Seoul offers work and residence visas to those whose parents or grandparents once held Korean citizenship—what is known as "overseas Koreans." However, Im Eun-Jin, an official at Seoul's Ministry of Justice, which handles immigration policy, says it is unlikely that Kopinos would qualify for those types of visas because their fathers are most likely still Korean nationals. For some in the group, there are few details on the father's identity.

Ms. Deladia credits Mr. Son and his wife for helping her make it through university. She earned a degree in business administration this year.

They want Kopinos to achieve their dreams, she says, "so Koreans don't look down on us."