Robert F. Kennedy, Jr., head of the Department of Health and Human Services, struck an alarmist tone about new findings that one in 31 eight-year-olds in the U.S. have an autism diagnosis at a press conference today.

Robert F. Kennedy Jr. is facing growing criticism from parents and advocates who say his recent comments on autism were misguided.

Kennedy, Hotez says, made a “false statement” in claiming that the scientific community denies that there are any environmental factors at play. “I’ve said to RFK Jr. that there could be an environmental component, but not vaccines, because autism occurs in fetal brain development well before kids ever see vaccines.”