The Amerasian Foundation (AF) and Amerasian Family Finder (AFF) define an Amerasian as "Any person who was fathered by a citizen of the United States (an American servicemen, American expatriate or U.S. Government Employee (Regular or Contract)) and whose mother is or was, an Asian National Asian." The term is commonly applied to half Japanese children fathered by a U.S. serviceman in Japan, as well as half Korean children fathered by veterans of the Korean War or stationary soldiers in South Korea. The term is also applied to children of Filipinos and American rulers during the U.S. colonial period of the Philippines (still used until today) and children of Thais and U.S. soldiers during World War II and the Vietnam War. The U.S. had bases in Thailand during the Vietnam War. Amerasian should not be interpreted as a fixed racial term relating to a specific mixture of races (such as Mestizo, Mulatto, Eurasian or Afro-Asian). The racial strain of the American parent of one Amerasian may be different from that of another Amerasian; it may be White, Black, Hispanic or even Asian. In the latter case, it is conceivable that the Amerasian could be fathered by a person who shares the same racial background but not the same nationality. In certain cases, it could apply to the offspring of American females, who engaged in professions such as military nurse, and Asian males. Mixed-race children, whatever the occupations of their parents, have suffered social stigma. With genetic relation to U.S. soldiers, Amerasians have faced additional exclusion by perceived association to military enemies of Asian countries. This stigma extended to the mothers of Amerasians, majority of whom were Asian, causing many of the Asian mothers to abandon their Amerasian children. The abandonment of both parents led to a large proportion of orphaned Amerasians. Since 1898, when the United States annexed the Philippines from Spain, there were as many as 21 U.S. bases and 100,000 U.S. military personnel stationed there. The bases closed in 1992 leaving behind thousands of Amerasian children. There are an estimated 52,000 Amerasians in the Philippines, but an academic research paper presented in the U.S. (in 2012) by an Angeles, Pampanga, Philippines Amerasian college research study unit suggests that the number could be a lot more, possibly reaching 250,000 this is also partially due to the fact that almost all Amerasian intermarried with other Amerasian and Filipino natives.