Kennedy's statements have raised concerns about his childhood vaccine commitment to Republican Senator Bill Cassidy.

But on Tuesday, speaking for the first time to thousands of U.S. Health and Human Services agency employees, he vowed to investigate the childhood vaccine schedule that prevents measles, polio and other dangerous diseases.

The U.S. Department of Health and Human Services issued guidance 'restoring concept of biological truth' after President Donald Trump's executive orders.

The new guidance follows President Trump’s demand that the Health and Human Services Department align with his executive order barring transgender athletes from women’s sports.

Robert F. Kennedy Jr., the Health Secretary, reaffirmed the Trump administration’s commitment to recognizing only two sexes, citing “biological truth” as the foundation for federal policy. The administration issued official sex-based definitions,