The ages of Joseph's plural wives are compared to other regions of 19th-century America.
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, MI: John Whitmer Books, 2010), 161-162
While on average Joseph Smith married older women than his 1880 peers, his wives' ages were more spread out. Though his percentage of teenage brides (30%) was slightly higher than a reasonable estimate for his peers in 1840s Illinois (20%), it was far from being historically high. One wonders if America could have met its "manifest destiny" of continental settlement so rapidly without adapting marital practices to the frontier.
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The thought of early marriage age coupled with a large age gap between spouses is not only foreign but repulsive to most modern Americans. . . .Nevertheless, in spite of contemporary marriage patterns--as well as exclamations of shock and accusations of Mormon pedophilia from critics of the Church--the indisputable reality is that in a large portion of the world and throughout most of history, marriage at a young age has been the norm.