Following the Manifesto of 1890 and the decline of officially-sanctioned plural marriages among the Latter-day Saints, many Mormons worked to construct explanations for the practice of polygamy. The discursive means used by Mormons to situate their peculiar institution in their past reveal insights into how Mormons saw themselves during the first decades of the twentieth century and how they wanted the world to perceive them. One strategy, highlighted here, was to downplay the significance of plural marriage in both practice and in doctrine. However, at the same time that this was occurring, many Mormons were arguing that polygamy had produced a large and righteous posterity, “racially” superior to other people born into monogamous families. B. H. Roberts presented one of the most insightful articulations of this narrative:
Plural wives among the Latter-day Saints, and first wives who consented to their husbands entering into these relations, accepted the institution from the highest moral and religious motives…that they might bear the souls of men under conditions that gave largest promise of improving the race and bringing forth superior men and women who shall lead the way to that higher state of things for which the world is waiting…its purpose was not earth-happiness, but earth-life discipline, undertaken in the interest of special advantages for succeeding generations of men. That purpose was to give to succeeding generations a superior fatherhood and motherhood, by enlarging the opportunities of men of high character, moral integrity, and spiritual development to become progenitors of the race; to give to women of like character and development a special opportunity to consecrate themselves to the high mission of motherhood. Race-culture, then, was the inspiring motive of the plural-wife feature of this revelation on marriage. It was in the name of a divinely ordered species of eugenics that the Latter-day Saints accepted plurality of wives (B.H. Roberts, The Truth, The Way, The Life: An Elementary Treatise in Theology, ed. John W. Welch, 2nd ed. [Provo: Brigham Young University Press, 1996], 556-57).
Roberts was not the first to postulate that Latter-day Saint plural marriage would produce superior offspring. Susa Young Gates argued in 1907 that “it would be difficult to find a finer race of men and women, morally, mentally, and physically, than has been produced through that order of marriage.” Josiah Edwin Hickman’s article “The Offspring of the Mormon People” was published in 1924 in the Journal of Heredity. Gates and Hickman both argued that the Mormons were physically, as well as morally superior to other people. This may have been a result, as Kathleen Flake argued, of Protestant characterizations of the children of polygamous marriages as stunted and malformed. In 1902, the Improvement Era published a missionary’s tribute to his mother, which reveals that Mormons were still very conscious of criticisms of alleged Mormon polygamous deformities, charges which had been made for decades:
When I think of the sacrifices which you, my dear mother, have made for the gospel’s sake-the severing of your family ties, the losing the love of an only brother, and the trials incident to celestial marriage-I cannot help thinking, as I look upon your face, (picture) before me: there is one of the noble women of the earth, a faithful mother in Israel, destined to become a queen in the kingdom of our God.
Oh! mother! They talk about the degradation of the “Mormons,” and the corruption of the plural marriage system. But, as I look into your face, I see gentleness, love, joy and purity, depicted in every line that marks your features.
My heart swells with emotion as I tell the enquirer to look upon that picture-my mother-the plural wife of my father, than whom no sweeter, purer woman ever lived.
Such are not the features of immoral practices, sorrow or slavery; but the fruits of keeping the commandments of God. The results of plural marriages as manifest in the intelligence, physical strength as well as in the features of the offspring of these relations are, and ever will be, man’s ever-able testimonies against those who assume to criticise, oppose and condemn this divine law.
Roberts however argues in the above quote that the motivation behind polygamy was to allow men and women of superior moral qualities to populate the earth, in preparation for the great destiny to come. Although he uses the words race and eugenics, no where does he imply that polygamy was intended to raise up seed that was physically superior to the rest of human kind. Roberts, however, is unclear as to how these moral traits were to be passed on. Were they to be inherited qualities, or were they to be acquired through instruction?
Note: While I am interested in the history of Mormon uses of eugenics, my primary interest here is in examining the inherently positive representations by Mormons after 1890 of their polygamous past (shaped by their participation in eugenics discourse) and how these positive representations should be understood in light of the trend of downplaying polygamy in other contexts. For a good summary of the overall history of Mormon participation in eugenics discourse, see the link to Sterling’s post in comment #1.
 Susa Young Gates, “A Message From a Woman of the Latter-day Saints to the Women of All the World,” Improvement Era 10, no. 5 (March 1907):
 Josiah Edwin Hickman, “The Offspring of the Mormon People,” Journal of Heredity 15 (1924): 55-68.
 A Missionary Boy, “Tribute to Mother,” Improvement Era 5, no. 3 (January 1902):