Craig L. Foster, David Keller, and Gregory L. Smith review demograpgic evidence for the age of Joseph's younger wives.
Craig L. Foster, David Keller, and Gregory L. Smith, “The Age of Joseph Smith's Plural Wives in Social and Demographic Context” in The Persistence of Polygamy: Joseph Smith and the Origins of Mormon Polygamy, ed. Newell G. Bringhurst and Craig L. Foster (Independence, Mo.: John Whitmer Books, 2010), 152–183
Were Joseph Smith's wives marital ages collectively normal reltive to their contemporaries? Did the Latter Day Saints' marriage patterns conform to marriage age patterns in other parts of the United States? We strongly suggest that Latter Day Saint marriage patterns and the age of Joseph's wives was well within the norm for their time and place on the nineteenth-century American frontier.