Seoul — The future of Korean children fathered by American soldiers remains uncertain despite a new law signed by President Reagan last month.
Discrimination by Koreans against these so-called ''Amerasian'' children is considered more severe than in other Asian nations where United States military forces have been based. Although there are not as many Amerasian children here compared to Southeast Asia, the continuing presence of US troops makes it an ongoing problem.
Racial purity is an integral part of the Korean tradition, and the Confucian ethic that underlies Korean thought and behavior patterns centers the family on the father - still the legal head of the family. A child whose looks betray foreign parentage is likely to suffer cruel teasing at school.
''My mother would shave me bald,'' said one blond-haired Korean Amerasian, ''people called me half-breed. . . .''
The new US legislation puts Amerasian children into the first preference category for immigrant visas. Previously they were classified in the seventh priority, which effectively denied permanent residence to the majority except under adoption programs. Now, between 20,000 and 80,000 Amerasians born in Korea , Vietnam, Laos, Thailand, and Kampuchea (Cambodia) could qualify for visas, residence permits, and social security cards.
Organizations and individuals concerned with the problems of Amerasian children in South Korea have long been lobbying for a change in US immigration law.
The Pearl S.Buck Foundation, set up to find and help Amerasian children, estimates there are about 6,000 of them in Korea. Korea-based director Donald Haffner says most of the 4,000 they have on file could now become eligible for entry to the US.
Under the terms of the new law, Amerasians will need an American sponsor able to provide financial support. This support is required to be at 125 percent of the US poverty level for five years or until the Amerasian is 21 years old, whichever is the longer. ''That's likely to mean at least 5,000 US dollars a year for five years,'' says Mr. Haffner. ''I think sponsors will be difficult to find.''
The Rev. Barry Flitcroft of the United World Mission agrees and fears that although technically the new law will give more opportunity to Amerasians over age 16 who don't qualify for adoption, the traditional and understandable preference for babies or young children will remain, leaving the older ones still unwanted and increasingly bitter as they see more and more young Amerasians leaving.
There may also be a tendency for Amerasians to drop out of school here, thinking they will soon go to America, he says, ''the magic day which for many of them will never arrive.''
One criticism already being made of the new law is that it will apply only to children fathered by an American citizen and born between 1950 and the day of enactment of legislation. With some 39,000 US soldiers still in Korea, the problem is likely to continue.