EBEYE, Marshall Islands - Playing in the streets, diving from rusted hulks of wrecked Navy ships into crystal-blue water, swinging makeshift bats in a game of baseball on dirt lots, doing back-flips from the remains of a mattress, the children are everywhere.

The Marshall Islands' fertility rate of 6.5 children per woman, defined as the number of children a woman can be expected to bear in her lifetime, is among the highest in the world. It is more than triple the U.S. figure of 2.1, which equals the replacement rate that demographers say keeps a country's population stable when factors such as emigration are not counted.

Slightly more than half the Marshalls' population of 50,800 in 2000 was under age 15. At the current growth rate, the islands' population could double in the next decade.

The islands' high birth rate and grinding poverty - per capita income is $2,300 a year and the unemployment rate more than 30 percent - combined with cultural and religious restrictions against abortion have made the Marshalls a major source of adoptive infants for American couples.

One Marshallese, Mohanna Henry, recounted how she was solicited by a "facilitator" for a U.S. adoption agency to give up her baby while waiting at a bus stop in Laura. She refused, but many others accept such overtures.

In a study of 73 Marshallese women who gave up their infants for adoption, Jini Roby, a professor at Brigham Young University, found that their average annual income was $400 and that the child they were giving up was often their fourth or fifth. Some had given birth to as many as 15 children.

From 1996 to 1999, the last year for which accurate figures were available, Americans adopted more than 500 Marshallese children, according to a study by Julianne Walsh Kroeker, a University of Hawaii anthropologist.

"If one were to consider the per capita adoption rate, the Marshall Islands would certainly have the highest rate in the world," her study concluded. Her figures showed that in 1998, that rate was .27 percent. The country with the next-highest rate was Guatemala, at .01 percent.

Those numbers led the Marshallese government to declare a moratorium in 1999 on adoptions by foreigners. That moratorium was lifted last year, after the Marshall Islands passed a law barring the promise or payment of money, gifts or other benefits to induce a birth mother to give up a child for adoption.

The legislation also creates a Central Adoption Authority, which is to act as a "central receiving point" for domestic and foreign adoptions and conduct "investigations into the backgrounds and circumstances under which an adoption is being proposed."

"I don't see any reason whatsoever why people can't come here [to the Marshall Islands] for adoptions and learn a little about their child's culture," said Roby, who was hired to organize the authority.

The law follows guidelines established by the Hague Convention on Intercountry Adoption, adopted in 1993. (A series of Hague conventions guide the practice of international law in 40 member countries, including the United States and most European Union nations.) Each signatory country agreed to create a central adoption authority to ensure that children are legally adoptable and that there have been no improper payments.

The State Department, which is responsible for ensuring that the conventions are followed in the United States, recently published proposed regulations in the Federal Register that will affect almost all countries that are major sources of adoptive children for U.S. parents, including China, Guatemala, Russia and South Korea.

Whether it will similarly affect the Marshall Islands commerce, in which pregnant women are flown to Hawaii and other U.S. states (Utah and Oklahoma are also frequent destinations), is unclear and sure to be the subject of litigation.

For now, adoption agencies can easily send island women to Hawaii because they need no visas to enter the United States. And among segments of Marshall Islands society, such adoptions continue to be tolerated because they ease population pressures and provide income to those involved in the industry.

One facilitator active in the islands is Sara Maun, who works with Noah's Ark Adoptions, a for-profit corporation licensed in Utah. She is the sister of Alik Alik, one of the prime sponsors of the islands' adoption law. At his law office and in her presence, Alik said he strongly disagreed with her and that he opposed the way she made a living.

But the hardscrabble nature of life in the Marshalls means that young mothers will continue to be susceptible to overtures to give up their children. Most Marshallese live jammed together in tin-roofed huts on narrow, horseshoe-shaped Majuro Atoll or on Ebeye, a tiny chunk of coral a ferry ride away from the sprawling U.S. military base on Kwajalein, site of a multibillion-dollar missile range.

The swimming pools, manicured lawns, golf course, tennis courts, bowling alley, and accommodations for U.S. military personnel and contractors provide a tantalizing glimpse of a richer lifestyle, unattainable for most Marshallese.

Playing on young mothers' hopes for a better life for their children, those in the adoption trade speak of their humanitarian motives in giving infants a chance to enjoy an American lifestyle.

"It is a good thing because we are helping the poor people," said Lane L. Lanny, who recruits Marshallese women willing to give up their babies.