They are South Korea's most precious exports - children sent abroad to start a new life free from the stigma of illegitimacy or other problems that brand them at home.

Tucked in blankets and strapped to airline seats, some 6,000 babies each year are sent to the United States alone, making South Korea the largest source of foreign orphans for American couples. By some estimates, 59 percent of all foreign adoptions in the United States are of Korean babies.It is not a record of pride for South Korean officials, who refuse to talk about foreign adoption or release statistics for fear of blemishing the nation's honor or giving a propaganda issue to its arch-rival, communist North Korea.

But the potential problem of profit-oriented adoption agencies forcing women to give up their infants prompts U.S. officials like American Embassy Immigration Officer Robert Ackerman, to ask "Where does humanitarianism end and business begin?"

The market in "humanitarian commerce," as one social worker wryly called it, is spurred by the laws of supply and demand.

U.S. couples want South Korean babies. Korea lacks a well-developed social- welfare network for unwed mothers and their estimated 14,000 illegitimate offspring born each year.

Domestic adoption is rare for cultural and historical reasons.

"Adoption unbalances the family tree," said one social worker.

Koreans guard their family heritage closely. Most families own a thick book tracing their lineage back thousands of years. Almost all South Koreans keep lists of given names handed down from generation to generation to be given to male children.

Korea is also a socially conservative society, and single women with children born out of wedlock are pushed to the fringes to labor at menial jobs or prostitution.

To cope with the problem, the South Korean government licenses four agencies to arrange overseas adoptions. Women who indicate they want to give up a child receive medical expenses from the agencies and are cared for at a home for unwed mothers until they deliver.

Most of the children are sent to the United States. Social workers locate an American couple and, for about $4,000, a contract is arranged. After the baby is born, the agencies contract with people flying back to the United States to take an infant along.

Richard Rife, legal counsel for the LDS Church in Korea, levels the most common complaint against the agencies.

"They lack the milk of human kindness," and care more about business than babies, he said.

But U.S. officials who monitor the agencies say their worst fear, baby selling, is not a serious problem - yet.

"It is obvious, in our experience, that baby selling is a possibility that is readily available at any time," says Ackerman of the U.S. embassy.

"When I see 500 kids going out of the country a month, I have to ask `do we have a humanitarian effort or just a baby pipeline?"'

But Ackerman says he has "reservations about condemning the system, because maybe it is a humanitarian issue."

There is a small but growing number of social workers that believes South Korea must now take care of its own orphans.

"After the (Korean) war, OK, we were poor," said one who insisted on anonymity. "But now we are a rich country. We should stop this."

There is some pressure inside the government to find a different solution for orphans because of potential embarrassment. North Korea has in the past used the issue of foreign adoptions to criticize the south as a nation unable to take care of its citizens.

So no health ministry official or agency representative will talk about adoptions.

"It is too sensitive an issue," said the public information director of the Holt agency, the nation's largest adoption agency.

Ackerman believes the rate of foreign adoptions will slow as South Korea continues to grow economically.

"Women will be more willing and able to keep their children" he says.

But some officials fear that agencies will pressure women into giving up their babies even if the mothers are ambivalent, because the agencies make money only when they send the babies abroad.

"At that point," Ackerman said, "there could be more pressure to keep the adoption system working."