New York City has fluoridated its tap water since 1965, when Mayor Eric Adams was 5 years old.

The U.S. Centers for Disease Control and Prevention lists water fluoridation as one of the country’s “Ten Great Public Health Achievements" of the 20th century.

A 2022 New York City health department publication advises parents to have their children drink tap water “to increase fluoride intake, since New York City water is fluoridated.”

But President-elect Donald J. Trump has promised to let Robert F. Kennedy Jr. “go wild on health,” and Mr. Kennedy, a vaccine skeptic and environmental lawyer who dropped his own bid for president and threw his support behind Mr. Trump, has advised doing away with water fluoridation.

Mr. Kennedy, who does not have a medical or public health degree, asserts that fluoride in water is associated with “arthritis, bone fractures, bone cancer, I.Q. loss, neurodevelopmental disorders and thyroid disease.” Mr. Trump has said Mr. Kennedy’s desire to reduce water fluoridation “sounds OK” to him.

This week, Mr. Adams, a conservative Democrat facing an April trial on federal corruption charges, seemed unsure of the merits of fluoridated water, too, deflecting questions about the issue for two days before eventually saying he supports fluoridation.

“I’m not too familiar with the whole conversation around fluoride, what makes it good or bad,” Mr. Adams said Wednesday, during his first news conference since the election of Mr. Trump.