Ten-year-old Pham Duc Duy is cradled in the arms of his mother, Nguyen Thi Thanh Van, 35, in their house in Hanoi June 16, 2007. Vietnamese doctors believe Duy, whose grandfather served in the Vietnam war, is a victim of exposure to dioxin passed down the generations. Several major U.S. chemical companies are directly accountable for supplying the U.S. military with dioxin, or "agent orange," during the Vietnam War and causing widespread dioxin poisoning, a lawyer for Vietnamese plaintiffs told a federal appeals court on June 18, 2007. Picture taken June 16, 2007. REUTERS/Kham (VIETNAM)

Pham Thi Thuy Linh, 10, reads a book at the Peace Village in Tu Du hospital in Ho Chi Minh City February 3, 2004. Pham was born with no arms in southern Vietnam where Agent Orange was sprayed during the war. REUTERS/Thomas White TW

Vietnamese defoliant Agent Orange victims lie on the bed at the Peace Village in Ho Chi Minh city September 15, 2006. Brain-damaged babies and children with shortened limbs and other physical deformities are still being brought to hospitals for specialized care, four decades after the United States sprayed Vietnam with the highly toxic defoliant. To match feature Vietnam-Dioxin. Photo taken on September 15, 2006. REUTERS/Kham (VIETNAM)

Vietnamese victims of the defoliant Agent Orange play at a social sponsorship centre in Vietnam's Danang city June 26, 2009. U.S. warplanes dropped about 18 million gallons of the defoliant on southern Vietnam for most of the 1960s. The defoliant released dioxins that have been blamed for health problems in people exposed. The United States has maintained there is no scientifically proven link between the wartime spraying and the claims of dioxin poisoning by more than 3 million people in Vietnam. REUTERS/Kham (VIETNAM CONFLICT HEALTH SOCIETY IMAGES OF THE DAY)

Agent Orange victims Chu Quang Duc, 27 years old, is assisted by his father, Chu Quang Chien, who served in Vietnam's central Quang Nam - Danang area from 1971-1975 during the Vietnam war, as they visit Friendship village, a hospice for Agent Orange victims outside Hanoi August 9, 2011. Delegates from around the world gathered in Hanoi for the second international conference on Agent Orange victims from August 8 to 10, on the occasion of the 50th anniversary of the introduction of Agent Orange/Dioxin into Vietnam. Agent Orange is a dioxin-laced defoliant sprayed by U.S. troops in the Vietnam War to destroy crops and jungle cover shielding guerrillas. U.S. warplanes used it the first time on August 10, 1961, in Vietnam's central Kontum province, dropping about 18 million gallons of the defoliant on southern Vietnam for most of the 1960s. The defoliant released dioxins that have been blamed for health problems on people exposed with claims of dioxin poisoning by more than 3 million people in Vietnam. REUTERS/Kham (VIETNAM - Tags: POLITICS HEALTH)

Heather Bowser, a second generation Agent Orange victim who's father Bill Morris was a U.S. soldier who served in Vietnam's southern Bien Hoa city from 1968-1969 during the Vietnam war, walks as she visits the Friendship village, a hospice for Agent Orange victims outside Hanoi August 9, 2011. Delegates from around the world gathered in Hanoi for the second international conference on Agent Orange victims from August 8 to 10, on the occasion of the 50th anniversary of the introduction of Agent Orange/Dioxin into Vietnam. Agent Orange is a dioxin-laced defoliant sprayed by U.S. troops in the Vietnam War to destroy crops and jungle cover shielding guerrillas. U.S. warplanes used it the first time on August 10, 1961, in Vietnam's central Kontum province, dropping about 18 million gallons of the defoliant on southern Vietnam for most of the 1960s. The defoliant released dioxins that have been blamed for health problems on people exposed with claims of dioxin poisoning by more than 3 million people in Vietnam. REUTERS/Kham (VIETNAM - Tags: POLITICS HEALTH)

Two young Vietnamese boys sit on the floor at the Peace Village in Tu Du hospital in Ho Chi Minh City February 3, 2004. Both boys were born in southern Vietnam where Agent Orange was sprayed during the war, and were abandoned at the hospital by their parents. TO ACCOMPANY FEATURE VIETNAM USA AGENTORANGE Picture taken February 3, 2004. REUTERS/Thomas White TW

A health worker helps an Agent Orange victim at the Friendship Village, a hospice for victims, in Hanoi August 10, 2009. Vietnam launched an "Orange Day" campaign on Monday to raise funds for people it says suffered through the spraying of Agent Orange herbicide by American forces during the war, for long an irritant in relations. REUTERS/Kham (VIETNAM SOCIETY POLITICS HEALTH CONFLICT)

Vietnamese defoliant Agent Orange Victim Pham Thi Thuy Linh, 12, types on the keyboard of a computer with her toes at the Peace Village in Ho Chi Minh city September 15, 2006. Brain-damaged babies and children with shortened limbs and other physical deformities are still being brought to hospitals for specialized care, four decades after the United States sprayed Vietnam with the highly toxic defoliant. To match feature Vietnam-Dioxin. Photo taken on September 15, 2006. REUTERS/Kham (VIETNAM)

Agent Orange victims learn to embroider at the Friendship Village, a hospice for victims, in Hanoi August 10, 2009. Vietnam launched an "Orange Day" campaign on Monday to raise funds for people it says suffered through the spraying of Agent Orange herbicide by American forces during the war, for long an irritant in relations. REUTERS/Kham (VIETNAM SOCIETY POLITICS HEALTH CONFLICT)

Vietnamese defoliant Agent Orange Victim Tran Huynh Thuong Sinh, 4, is seen at the Peace Village in Ho Chi Minh city in this September 15, 2006 file photo. Brain-damaged babies and children with shortened limbs and other physical deformities are still being brought to hospitals for specialized care, four decades after the United States sprayed Vietnam with the highly toxic defoliant. To match feature Vietnam-Dioxin. REUTERS/Kham/Files (VIETNAM)

Hoa (R) and Nhon, both born with stunted limbs and 12 fingers, stand at their front door at their home in Dong Ha 70 km (44 miles) north of Hue in central Vietnam, February 4, 2004. Their father, Le Huu Dong, served as a south Vietnamese soldier and had lived with his wife near an American airbase along the Laos/Vietnam border from 1966 - 1967. Le, who has three daughters with the same deformities, said he was sprayed frequently with Agent Orange during the war. Three Vietnamese who say they are victims of Agent Orange have filed the first lawsuit on January 30, 2004 against the companies that made the chemical, state media said. REUTERS/Thomas White TW/DL

Agent Orange victims are seen at the Friendship Village, a hospice for victims, in Hanoi August 10, 2009. Vietnam launched an "Orange Day" campaign on Monday to raise funds for people it says suffered through the spraying of Agent Orange herbicide by American forces during the war, for long an irritant in relations. REUTERS/Kham (VIETNAM SOCIETY POLITICS HEALTH CONFLICT)

Vietnamese defoliant Agent Orange Victims Nguyen Xuan Minh (L), 5, and Nguyen Thi Thuy Giang, 25, of Hanoi are seen at the Peace Village in Ho Chi Minh city in this September 15, 2006 file photo. Brain-damaged babies and children with shortened limbs and other physical deformities are still being brought to hospitals for specialized care, four decades after the United States sprayed Vietnam with the highly toxic defoliant. To match feature Vietnam-Dioxin. REUTERS/Kham/Files (VIETNAM)

An Agent Orange victim carries food for lunch at a hospice in Vietnam's central Da Nang City June 16, 2011. The U.S. and Vietnam launched the first concrete step towards cleaning up contamination from Agent Orange on Friday, in what the top U.S. diplomat in the country said was one of the most significant developments ever in bilateral ties. Agent Orange was a dioxin-laced defoliant sprayed by U.S. troops in the Vietnam War to destroy crops and jungle cover shielding guerrillas. Picture taken June 16, 2011. REUTERS/Kham (VIETNAM - Tags: HEALTH POLITICS ENVIRONMENT CONFLICT)

A disfigured arm of a Vietnamese boy disabled by Agent Orange strokes another victim in a Ho Chi Minh City hospital, February 25, 2005. [On Monday, a New York court will begin hearing a lawsuit brought by more than 100 Vietnamese seeking compensation and a clean-up of contaminated areas from more than 30 firms, among them Dow Chemical Co and Monsanto Co, the largest makers of Agent Orange. Agent Orange, named after the colour of its containers, is blamed for nightmarish birth defects in Vietnam where babies appeared with two heads or without eyes or arms.]

Hong, 24, who claims to be a victim of Agent Orange, stands on the front porch of his housing at the Friendship Village project in Hanoi November 15, 2006. Agent Orange, a weed killer containing dioxin, was widely used during the Vietnam War. REUTERS/Adrees Latif (VIETNAM)

Pham Thi Thuy Linh, 10, writes with her foot at the Peace Village in Tu Du hospital in Ho Chi Minh City February 3, 2004. Pham was born with no arms in southern Vietnam where Agent Orange was sprayed during the war. REUTERS/Thomas White TW

Vietnamese children who doctors say are suffering from birth defects due to their parents' exposure to chemical defoliants during the Vietnam War race wheelchairs in the grounds of the Vietnam Friendship Village near Hanoi January 4. Tom Corey, national vice-president of the Vietnam Veterans of America, Inc said on Monday that Washington could this year finally release money to fund research into the wartime use of Agent Orange and other defoliants. During the Vietnam War, the United States sprayed millions of litres of chemical defoliants over vast areas of the country. Vietnam says around two million adults were exposed and affected, while there are around 100,000 children who suffer defects due to their parents' exposure.

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Nurses feed children with birth defects as a result of their parents exposure to the defoliant Agent Orange in a special wing reserved for the children at the Tu Du Women's Hospital in Ho Chi Minh City November 14, 2000, [a few days before a visit to Vietnam by U.S. President Bill Clinton]. Hanoi says that the U.S. has a moral responsibility to do more to help alleviate the suffering caused by the Vietnam War including the legacy of the toxic defoliant used by U.S. forces that Vietnam blames for causing tens of thousands of birth defects.

Soldiers detect Unexploded Ordnance (UXO) and defoliant Agent Orange during the launch of the "environmental remediation of dioxin contamination" project, in Vietnam's central Da Nang City June 17, 2011. The U.S. and Vietnam launched the first concrete step toward cleaning up contamination from Agent Orange on Friday in what the top U.S. diplomat in the country said was one of the most significant developments ever in bilateral ties. Agent Orange was a dioxin-laced defoliant sprayed by U.S. troops in the Vietnam War to destroy crops and jungle cover shielding guerrillas. REUTERS/Kham (VIETNAM - Tags: HEALTH POLITICS ENVIRONMENT MILITARY CONFLICT IMAGES OF THE DAY)