Scott Davidson has always liked a challenge. This year, the 46-year-old ultramarathoner ran 100 continuous miles through his home state of Nevada, racing over roads and trails through the wind and darkness.

He did it on two prosthetic legs.

Davidson was born with severe birth defects, including deformities of his lower limbs and jaw that required surgery when he was young. For much of his life, he thought his birth defects were idiopathic—from an unknown cause. But after reading online message boards and getting multiple messages from researchers asking if his father was a Vietnam veteran, he now believes his conditions were caused by his father’s exposure to Agent Orange during the Vietnam War.

Agent Orange, an herbicide sprayed extensively during the Vietnam War, contained dioxin, a toxic chemical linked to cancer.

But when Davidson applied to the Department of Veterans Affairs for medical benefits in 2023, his claim was denied. For many birth defects, VA benefits are available to children whose mother served in Vietnam. Children of male Vietnam veterans, like Davidson, generally qualify only if they have spina bifida.

It’s a policy Davidson is trying to change.

“As a country, we pride ourselves on being very intelligent, well researched, capable of handling things, yet we are so outdated in our approach to birth defects,” he said.

That’s why Davidson’s next challenge isn’t on a mountain or trail. It’s in the halls of Congress.

Davidson is working with lawmakers on a bill called the Children of Toxic Exposure Relief Act, which he says would expand VA benefits to children of male Vietnam War veterans and to some children of veterans who served in other areas where Agent Orange was used, like Thailand.

The proposal is still being developed and has not yet been introduced, according to a congressional staffer familiar with the effort. Sen. Richard Blumenthal, D-Conn., and Sen. Jacky Rosen, D-Nev., have expressed support.

“Children of veterans exposed to toxins deserve our support without exception,” Blumenthal said in a statement to The War Horse. “The damage caused by Agent Orange is well-documented, and denying benefits solely because the father of the impacted child served rather than the mother is both unjust and cruel.”

The bill could face hurdles when it gets to Congress. The lawmakers are still looking for Republican supporters, and expanding eligibility could open VA to approximately 350,000 new claims by children of male Vietnam veterans, according to lawyers from Yale Law School, which could amount to tens of millions of dollars.

Davidson is not alone in pushing for change. Through litigation and proposed legislation, veterans’ families and advocates are fighting to help these children—many now middle-aged—receive benefits.

“This is a multigenerational problem,” said Brandie Matthews, an advocate for children of male Agent Orange survivors and the daughter of a Vietnam veteran. “It’s not going away anytime soon.”

The Controversial Science of Birth Defects

There are no precise figures for how many U.S. service members were exposed to dioxin, the toxic chemical in Agent Orange, during the Vietnam War. The United States sprayed more than 19 million gallons of herbicides during the war, primarily to clear away dense foliage.

Estimates suggest that between 2.6 and 3.8 million service members may have been exposed to herbicides, including Agent Orange, between 1962 and 1971. While more than 10,000 women served in Vietnam, the overwhelming majority of those potentially exposed were men.

But VA benefits for many birth defects are available only to children of women who served in Vietnam from 1961 to 1975, roughly the same period when Agent Orange was sprayed there. VA awards those benefits based on the mother’s service in Vietnam, not on a finding that the birth defects were caused by Agent Orange or dioxin exposure.

Spina bifida is the major exception: VA will provide benefits to children of both male and female veterans of the war suffering from the condition.

That distinction is written into federal law and is not simply VA policy. Congress created the benefits program for children of women Vietnam veterans in 2000, meaning VA cannot on its own extend the same eligibility to children of male veterans.

On its website, VA points to a 2018 National Academies review that found “insufficient evidence” to determine whether paternal exposure to Agent Orange is associated with birth defects.

The report said there are biological ways a father’s exposure could affect his children, but the evidence so far is not strong enough to prove that it does. Animal studies have also found reproductive and developmental problems after exposure to dioxin and related chemicals.

Scientists remain divided over what conclusions can be drawn from the evidence.

Michael Skinner, a Washington State University researcher who studies how the environment influences reproduction, said it can be hard to determine whether a specific birth defect was caused by Agent Orange or another toxin.

“It would be difficult to say it was your father’s or grandfather’s exposure during Vietnam that was the cause,” he wrote in an email, “due to the many other things we are now daily exposed to.”

In 2020, Jamaji Nwanaji-Enwerem, a doctor and professor at the University of Pennsylvania, published a study that found male Vietnam veterans with higher levels of dioxin in their blood had sperm that was potentially less healthy and showed signs of accelerated biological aging.

But Nwanaji-Enwerem cautioned that the finding does not show that dioxin exposure causes birth defects.

“There is growing evidence that the sperm epigenome can influence offspring health, but the field is still early,” he wrote in an email. “Our study did not examine children or birth outcomes directly, so anything in that direction remains speculative at this point.”

Other researchers have drawn stronger conclusions.

George Knafl, a statistician and emeritus professor at the University of North Carolina at Chapel Hill School of Nursing, has spent the better part of a decade reanalyzing data from a major Air Force study of children of Vietnam veterans. Originally, Knafl was commissioned by Vietnam Veterans of America to redo the statistical analysis. Later on, he continued the work on his own. In a series of papers, Knafl has found that children of male veterans with higher dioxin exposure had greater odds of birth defects.

“In many cases, their chance of having a defect went up as you have higher levels of dioxin exposure,” Knafl said. “That’s my finding. So I let other people decide whether they believe it or not.”

Other analyses have pointed in the same direction. In 2016, ProPublica analyzed VA data and found that Vietnam veterans exposed to Agent Orange had more than one-third higher odds of having a child with a birth defect.

The VA, however, continues to rely on the National Academies review, which says there is not enough evidence of the association between a father’s dioxin exposure and his children’s birth defects.

Despite the scientific uncertainty, many Vietnam veterans and their children believe Agent Orange exposure has impacted their health.

Earlier this year, Sharon Atienza, a nurse whose father served in Vietnam, published a study after interviewing 20 children of male Vietnam veterans. She found that many children of Vietnam veterans worry about the potential generational effects of Agent Orange and feel frustrated that the government has not validated those concerns.

Atienza said more research could help address some of those concerns.

A good first step, she said, would be a disease registry that tracks illnesses and birth defects of children born to fathers exposed to Agent Orange. “That way we have a database, and we can compare that to the general public,” she said.

One such registry does exist, though it is not a government database. The nonprofit advocacy group Birth Defect Research for Children has collected thousands of self-reported birth defects from children of parents exposed to Agent Orange and compared them to children of unexposed parents.

In a 2024 analysis of more than 6,000 children in the registry, the organization reported higher rates of several conditions among children of male Vietnam veterans, including seizures, scoliosis, and vision problems.

Because the registry relies on voluntary, self-reported data, the findings cannot establish that Agent Orange caused those conditions. But advocates say it shows why more rigorous government research is needed.

“We have presented the data to Congress, both the House and the Senate,” said Betty Mekdeci, the organization’s executive director. “We certainly have presented information to all of the veterans groups, you name it, and nothing’s been done.”

Suing the Department of Veterans’ Affairs

One father-daughter duo is done waiting for the scientific debate to be resolved. They are challenging the VA policy in court.

Ron Christoforo enlisted in the Army during the Vietnam War and served as a telecommunications technician. He said when he got to Vietnam, each helicopter landing zone he traveled to had been cleared with Agent Orange to push back the jungle foliage for about 300 feet, so no one could hide and ambush the helicopters. At the time, he said, troops had little idea that Agent Orange exposure might affect their health decades later.

“We didn’t talk about it,” he said. “We just knew that we had to clear areas, otherwise it would be all jungle.”

In 1992, years after Ron returned from Vietnam, his daughter Michele was born with achondroplasia, a rare genetic defect that causes dwarfism. Neither Ron nor his wife had a family history of the condition. The disease is often caused by a spontaneous gene mutation and isn’t hereditary, according to the National Institutes of Health.

Growing up, Michele said, she faced discrimination.

“People made fun of me,” she said, “but then after they got to know me, it was better.”

Years later, Michele was watching “The Little Couple,” a television show about two people with dwarfism, when she learned that the father of one of its stars had also served in Vietnam. The coincidence made her wonder whether her father’s Agent Orange exposure could be connected to her condition.

She applied for VA benefits but was denied. Achondroplasia is among the conditions for which VA provides benefits to children of female Vietnam veterans, but Michele was told she would not qualify because her father, not her mother, had served in Vietnam.

When VA rejected Michele’s claim, “I was very dejected,” Ron said. “The sacrifices that we made as a family here actually meant nothing.”

Michele and Ron decided to challenge the policy in court. In April 2026, they sued VA, alleging that the different treatment of children of male and female Vietnam veterans amounts to unconstitutional sex discrimination.

“We always want our best for our kids,” Ron said. “And in my case, not only do I want the best, but I want her to have the medical [care] that she’s going to need later and some financial assistance she’s going to need.”

When asked why VA does not provide benefits to children of male Vietnam veterans, spokesperson Quinn Slaven said, “VA does not comment on pending litigation.”

Michele said VA benefits could help her move out of her parents’ home and into housing adapted to her needs, with accessible countertops, chairs, and a bathroom. She also hopes the benefits could help her afford a wheelchair as her arthritis progresses.

The case is on hold while the courts consider a separate veterans-benefits case before the Supreme Court this fall.

A Bill for More Research

Some advocates believe cost is a major reason VA has not expanded benefits to the children of male Vietnam veterans.

“It’s strictly economics,” said Mekdeci. “They don’t want to pay for this.”

Brandie Matthews, the advocate and daughter of a Vietnam veteran, feels the same way.

“It’s money,” she said. “It’s not the medical side, it’s the business side. Think about how many males went to Vietnam versus females.”

Other advocates argue that the first step is more research into whether toxic exposures can affect veterans’ descendants.

That’s the goal of the Molly R. Loomis Research for Descendants of Toxic Exposed Veterans Act. The bill, named for a woman with spina bifida whose father was a Vietnam veteran, was passed by the Senate Veterans’ Affairs Committee in March. It would direct VA to conduct research into health conditions among descendants of veterans exposed to toxic substances. The measure would cover Agent Orange as well as other military toxic exposures.

The measure was later folded into the broader Take Care of America’s Veterans Act, which includes dozens of veterans-related provisions. The larger bill has stalled in the House over a controversial proposal to cut some future veterans’ benefits.

For Davidson, however, research is not enough. He believes VA should begin accepting claims from descendants of veterans exposed to Agent Orange now.

“The intention is good,” he said. But, he added, “Every research study, it’s just more of the same. It just buys time to not accept claims.”

This article from The War Horse was edited by Paul Szoldra, fact-checked by Trey Strange, and copy-edited by Mitchell Hansen-Dewar.