The practice of adopting children from abroad began just after World War II when large numbers of children were orphaned, abandoned, or separated from their parents as a result of the war in Europe. Americans, eager to provide humanitarian assistance, were moved by the plight of innocent children affected by the devastation of war, and adoptions began in the 1940s.

It was the Korean War (1950-53), however, which signaled the beginning of the largest wave of international adoptions to take place worldwide. Since the War, South Korea has expedited the adoptions of over 200,000 Korean children (about 150,000 to the U.S., and 50,000 to Europe, Canada and Australia), and continues to send children overseas today. For three decades, South Korean children constituted the largest number of foreign-born adoptees to enter the U.S. on an annual basis, a status that changed only in 1991, when adoption of foreign children was led by Romania (2,552 children vs. 1,817 Korean children). In 1999, the number of adopted South Korean children (2,008) ranked third after Russia (4,348) and China (4,101) (source: National Adoption Information Clearinghouse). To date, Koreans remain the largest group of adoptees in both the U. S. and Western Europe.

In the 1970s, another war in Vietnam precipitated increased adoptions by American families. "Operation Baby Lift" in 1975, was a series of highly publicized "humanitarian" rescue operations that brought at least 2,000 Vietnamese and mixed-raced children (many fathered by American GIs) to the U.S. for eventual adoption. Approximately 1,300 children were also flown to Canada, Europe and Australia. The hasty evacuation in the final days of the war led to a public debate over whether these actions had been in the best interest of the children and whether the children would have been better served by remaining in Vietnam. Some critics asserted that the "Baby Lift" represented another form of American cultural imperialism. The greatest point of controversy, however, had to do with the circumstances that led to the relinquishment of the "Baby Lift" children and whether these children were technically orphans who qualified for adoption. Lost or inaccurate records were the norm and, in several cases, birth parents or other relatives who later arrived in the U.S. demanded custody of children who had previously been adopted by American families.

Beginning in the mid-1980s, Americans began traveling to Central and Latin America to adopt, including Peru, Honduras, Guatemala, Mexico and El Salvador, also torn by war. Adoptions from Guatemala have risen substantially, and now represent the fourth largest number of foreign adoptions by American families (1,002 in 1999, up from 621 children in 1997).