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.

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

Mr. Kennedy appears to have most Republicans behind him as he seeks the job of health secretary, though he couldn’t escape his past stances on vaccines and abortion.

Robert F. Kennedy Jr. faced aggressive questions about his skepticism of vaccines and other issues during the first of two scheduled Senate confirmation hearings.

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

Robert F. Kennedy Jr. arrived at his confirmation hearing to lead the Department of Health and Human Services ready for battle—and wasted no time rallying a demographic that has been among his most loyal soldiers.

Caroline Kennedy, daughter of former President John F. Kennedy, warned senators of her “predator” cousin ahead of his first confirmation hearing on Wednesday. In a letter first reported by The Washington Post, she wrote that his victims included family members and parents of sick children.

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.