Introduction On April 10, 2025, US Health and Human Services Secretary Robert F. Kennedy, Jr, stated during a White House Cabinet meeting that “in September, we will know what has caused the autism epidemic.”1 On September 22, 2025, President Trump and Secretary Kennedy unexpectedly promoted leucovorin as a treatment for speech-related deficits associated with autism spectrum disorder (ASD).2 Leucovorin, also known as folinic acid, is a biologically active, partially reduced form of folic acid.