President-elect Donald Trump has picked Robert F. Kennedy Jr. as his Health and Human Services secretary and while we don’t know what the policies will be, one thing Kennedy has signaled he would look at is fluoridation of water across the United States.

The Washington Post and other media noted that medical organizations responded by calling Kennedy’s assertions unfounded at the levels of fluoridation used in drinking water. But many of them have also noted that in an NBC interview, Trump said possible action against fluoridation of water “sounds OK to me ... You know, it’s possible.”

Florida’s Surgeon General is the latest high-profile politician to advise against adding fluoride to drinking water. For decades it’s been credited with keeping teeth healthy, but now some are starting to question if it is necessary or even harmful in high doses.