HERE is the uncomfortable truth about autism: we know little about the many causes of this spectrum of disorders, nor how to treat them in an effective way. Feeling abandoned by mainstream medicine, some parents are driven to try unorthodox “cures” (see “The lure of a cure for autism”). This is dangerous territory.

Most likely, these treatments do nothing. Some may help, though without proper trials we can’t be sure. Some can also have dangerous side effects.

While behavioural therapies don’t eliminate autism, they have at least been properly tested and are known to lessen symptoms. What is clear …