In the space of a few months, a high-school senior fed up with his parents’ anti-vaxxer beliefs went from a subreddit called NoStupidQuestions to the halls of Congress.

Ethan Lindenberger, who inserted himself into a national debate by getting himself immunized this December, appeared before a U.S. Senate subcommittee on Tuesday to school lawmakers about the misinformation that fueled his family’s skepticism.

“My mother is an anti-vax advocate [who] believes that vaccines cause autism and brain damage, and does not believe that they contribute to the health and safety of society, despite the fact that such opinions have been debunked numerous times by the scientific community,” the 18-year-old Ohioan told the panel.

“I went my entire life without numerous vaccines against diseases such as measles, chicken pox, and even polio.”

Two outbreaks of measles—one in the Pacific Northwest and one in New York State—have highlighted the danger of the anti-vaxxer movement that attracted Lindenberger’s parents.

Sitting behind a white placard bearing his name in Room 430 of the Dirksen Senate Office Building, their son told the committee how he grew up thinking that vaccines caused harm.

But as he got older, he stopped buying it.

“As I approached high school and began to critically think for myself, I saw that the information in defense of vaccines outweighed the concerns heavily,” he said.

“I began leading debate clubs in my school and pursuing truth above all else, and I realized one certain quality in debates [...] there seems to always be two sides to a discussion.”

“This is not true for the vaccine debate,” he said.

When he approached his mother with articles from the CDC, urging her to vaccinate the family, he said she brushed him aside. “That’s what they want you to think,” she told him.

On Nov. 16 he posted a query on r/NoStupidQuestions, titled “My parents are kind of stupid and don't believe in vaccines. Now that I’m 18, where do I go to get vaccinated? Can I get vaccinated at my age?”

“Because of [my parents’] beliefs I’ve never been vaccinated for anything, god knows how I’m still alive,” he wrote, adding, “Any advice would be awesome.”

Concerned Redditors quickly jumped in with guidance about health insurance and parental consent. Lindenberger appended an edit to the post soon after, explaining that while his mom was “especially angry,” he had a doctor’s appointment scheduled a few weeks out.

And on December 17, just over a month after his initial post, he succeeded. “Finally got my vaccines!” he wrote.

In Washington, Lindenberger told the senators that he doesn’t blame his mother—he faults the misinformation online that manipulated her fear and her love for her children.

“My mother came from a sense of loving her children and being concerned,” the teen insisted, adding that those who spread misinformation online “instill fear into the public for their own gain selfishly, and do so knowing that their information is incorrect.”

While he was lauded by senators for his bravery and leadership, not all the lawmakers on the panel echoed his sentiments.

“It is wrong to say that there are no risks to vaccines,” Sen. Rand Paul (R-KY) said during the session, voicing opposition to mandatory shots. He later added, “I believe that the benefits of vaccines greatly outweigh the risks, but I still do not favor giving up on liberty for a false sense of security.”

The U.S. is seeing the risks of vaccine hesitancy in stark terms. Measles was considered eliminated in 2000, but now nearly 70 people—the vast majority of them unvaccinated children—have gotten the potentially deadly virus in the Pacific Northwest and another 200-plus have fallen ill in Orthodox Jewish communities in New York.

Health officials blame anti-vaxxers for the spread of measles, while anti-vaxxers moan that they are being demonized.

Lindenberger said he feels for parents who want to do right by their children and are taken in by zealots allowed to spread to their debunked theories through the internet.

“For my mother, her love and care for her children was used to create a false distress,” he said. “And these sources, which spread this misinformation, should be the primary concern of the American people.”