For the first time in modern American history, a skeptic of medical research could be responsible for safeguarding public health.

If approved, Kennedy will control a $1.7 trillion agency that oversees food and hospital inspections, hundreds of health clinics, vaccine recommendations and health insurance for roughly half the country.

Kennedy's condition is called spasmodic dysphonia, which is a neurologic disorder that can affect the voice and speech by causing the muscles that generate a person’s voice to go into periods of spasm, according to Penn Medicine. It is a lifelong condition, but can be improved with treatment in some cases, according to Penn Medicine.

Robert F. Kennedy Jr.'s long record of questioning the safety of childhood vaccinations persisted as a flash point for him Thursday during a confirmation hearing where a key Republican quickly raised concerns about his views.

Robert F. Kennedy Jr. has said vaccines are not safe. His support for abortion access has made conservatives uncomfortable.

Robert F. Kennedy Jr. was confronted with a number of his baseless claims and a vexing abortion issue. But Republican senators treaded lightly.

Robert F. Kennedy Jr., a former presidential candidate and environmental activist, endorsed Donald Trump last year and threw his weight behind a campaign to “Make America Healthy Again.” For the past two decades he has been best known for airing skeptical views on vaccines.

Some Senate Republicans who would confirm Robert F. Kennedy Jr.'s as the nation's top health official are uncomfortable with his views on abortion access and banning corn syrup and pesticides from America's food supply.