A gastroenterologist who persuaded millions of parents worldwide that the vaccine used to prevent measles, mumps and rubella might cause autism has been banned from practicing medicine in his native Britain after the country's top medical group said Monday he conducted his research unethically. Dr. Andrew Wakefield was the first researcher to publish a peer-reviewed study suggesting a connection between autism, inflammatory bowel disease and the MMR vaccine. In February, Britain's leading medical journal, "The Lancet, "retracted Wakefield's controversial 1998 study just days after Wakefield was found guilty by a British panel of acting unethically in his research on autism....