Polygamy and Population Growth

Does the Book of Mormon teach that polygamy is instituted by God to "raise up seed"?

Yes. Jacob 2 states, "For if I will, saith the Lord of Hosts, raise up seed unto me, I will command my people."[1]

Did polygamy actually increase the population in Utah more than it would have otherwise?

Yes, probably. Studies have shown that societies where a man can have more than one wife tend to have many more children than other societies,[2] and Latter-day Saints had a lot of children relative to the rest of the U.S. at the time, particularly while polygamy was practiced.[3]

Youth of Utah Relative to the U.S. According to Census Numbers[4]

But isn't it true that plural wives have fewer children than non-plural wives?

Yes individually, but overall, no. Latter-day Saint plural wives, (and plural wives in other societies[5]) generally had fewer children than their non-plural wife counterparts.[6] However, polygamy leads to fewer unmarried women,[7] which increases the number of children born overall.[8]

So if non-plural wives have more children than plural wives, wouldn't the population have increased even more if polygamy wasn't practiced?

Probably not. Without polygamy, the marriage rate would probably have been lower.[9] Several early Church sources suggested that there were more women than men in the early Church and that polygamy helped provide homes and spouses for these women.[10]

Why would the marriage rate be lower without polygamy? Was there a disparity between men and women in Utah at the time?

Possibly, it's unclear. There wasn't a significant disparity between men and women at the time.[11] Some research has indicated that women were more religious than men at the time as a possible reason for polygamy.[12]

The Facts

  • The Book of Mormon indicates that polygamy is instituted to "raise up seed unto [the Lord].

  • Plural wives in the nineteenth century individually had fewer children than non plural wives.

  • There was an increase in the overall birth rate in Utah due to plural marriage because polygamy led to fewer unmarried women.

Our Take

The history of polygamy can be uncomfortable, and so often, people discuss possible reasons or justifications for the practice. Those reasons aren't always clear though. The scriptures tell us that polygamy was to "raise up seed"—did that actually work?

There is some data from census records and other studies on how polygamy affected the Utah population. That data indicates that polygamy increased the population more than comparable non-polygamous populations at the time. It seems that though polygamous wives had fewer children, polygamous populations disproportionally increased because in polygamous communities more women married and had children.

Understanding polygamy, and the reasons for it, is more complicated than simply stating it was for increasing the population. There are many more legitimate questions about polygamy, and it's okay to acknowledge the messiness and complexities of the topic. Commandments from God can have temporal justifications, but Latter-day Saints rely on faith as they make sense of something like polygamy.

What's Your Take?

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These takes are curated for a general audience and may contain minor edits when posted.
  • Stephen
    I tend to think that the “raise up seed” concept is couched somewhere in the Abrahamic Covenant. All “seed” is ultimately God’s seed. But, for some reason “seed unto myself” is different. Perhaps it’s a way that God fulfills His Covenant more than increasing a certain population?