D.D. Palmer founded chiropractic in the 1890s and his son B.J. Palmer helped to expand it in the early 20th century. It has two main groups: "straights", now the minority, emphasize vitalism, innate intelligence and spinal adjustments, and consider subluxations to be the leading cause of all disease; "mixers" are more open to mainstream and alternative medical techniques such as exercise, massage, nutritional supplements, and acupuncture. Chiropractic is well established in the U.S., Canada and Australia.